diff --git a/changelog.d/statute-bugs-ar-ky-wv.fixed.md b/changelog.d/statute-bugs-ar-ky-wv.fixed.md
new file mode 100644
index 00000000000..3c56954340b
--- /dev/null
+++ b/changelog.d/statute-bugs-ar-ky-wv.fixed.md
@@ -0,0 +1 @@
+Fix Arkansas income-tax indexing projections, Kentucky's 2021 dependent care credit conformity, and West Virginia's treatment of 529 contributions in senior and disability modifications.
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/bracket_adjustment.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/bracket_adjustment.yaml
index 0a2268342f7..0ca022e7897 100644
--- a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/bracket_adjustment.yaml
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/bracket_adjustment.yaml
@@ -5,6 +5,8 @@ metadata:
   amount_unit: currency-USD
   label: Arkansas high-income bracket adjustment
   reference:
+  - title: A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2 (annual CPI-U indexing capped at three percent)
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
   - title: A.C.A. § 26-51-201(a)(4)(C), as amended by Act 1 of 2026 (1st Extraordinary Session), § 1
     href: https://www.arkleg.state.ar.us/Home/FTPDocument?path=%2FACTS%2F2026S1%2FPublic%2FACT1.pdf#page=2
   - title: A.C.A. § 26-51-201(d)(1), as amended by Act 532 of 2023, § 2 (bracket amounts indexed annually, rounded to the nearest $100)
@@ -22,7 +24,7 @@ brackets:
         2026-01-01: 94_700
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -33,7 +35,7 @@ brackets:
         2026-01-01: 94_800
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -44,7 +46,7 @@ brackets:
         2026-01-01: 94_900
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -55,7 +57,7 @@ brackets:
         2026-01-01: 95_000
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -66,7 +68,7 @@ brackets:
         2026-01-01: 95_100
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -77,7 +79,7 @@ brackets:
         2026-01-01: 95_200
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -88,7 +90,7 @@ brackets:
         2026-01-01: 95_300
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -99,7 +101,7 @@ brackets:
         2026-01-01: 95_400
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -110,7 +112,7 @@ brackets:
         2026-01-01: 95_500
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -121,7 +123,7 @@ brackets:
         2026-01-01: 95_600
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -132,7 +134,7 @@ brackets:
         2026-01-01: 95_700
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -143,7 +145,7 @@ brackets:
         2026-01-01: 95_800
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -154,7 +156,7 @@ brackets:
         2026-01-01: 95_900
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -165,7 +167,7 @@ brackets:
         2026-01-01: 96_000
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -176,7 +178,7 @@ brackets:
         2026-01-01: 96_100
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -187,7 +189,7 @@ brackets:
         2026-01-01: 96_200
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -198,7 +200,7 @@ brackets:
         2026-01-01: 96_300
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -209,7 +211,7 @@ brackets:
         2026-01-01: 96_400
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -220,7 +222,7 @@ brackets:
         2026-01-01: 96_500
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -231,7 +233,7 @@ brackets:
         2026-01-01: 96_600
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -242,7 +244,7 @@ brackets:
         2026-01-01: 96_700
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -253,7 +255,7 @@ brackets:
         2026-01-01: 96_800
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -264,7 +266,7 @@ brackets:
         2026-01-01: 96_900
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -275,7 +277,7 @@ brackets:
         2026-01-01: 97_000
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -286,7 +288,7 @@ brackets:
         2026-01-01: 97_100
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -297,7 +299,7 @@ brackets:
         2026-01-01: 97_200
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -308,7 +310,7 @@ brackets:
         2026-01-01: 97_300
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -319,7 +321,7 @@ brackets:
         2026-01-01: 97_400
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -330,7 +332,7 @@ brackets:
         2026-01-01: 97_500
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -341,7 +343,7 @@ brackets:
         2026-01-01: 97_600
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/rate.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/rate.yaml
index 643edacf349..49201402b8e 100644
--- a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/rate.yaml
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/rate.yaml
@@ -5,6 +5,8 @@ metadata:
   rate_unit: /1
   label: Arkansas high-income tax table
   reference:
+  - title: A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2 (annual CPI-U indexing capped at three percent)
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
   - title: A.C.A. § 26-51-201(a)(4)(B), as amended by Act 1 of 2026 (1st Extraordinary Session), § 1
     href: https://www.arkleg.state.ar.us/Home/FTPDocument?path=%2FACTS%2F2026S1%2FPublic%2FACT1.pdf#page=2
   - title: A.C.A. § 26-51-201(d)(1), as amended by Act 532 of 2023, § 2 (bracket amounts indexed annually, rounded to the nearest $100)
@@ -21,7 +23,7 @@ brackets:
         2026-01-01: 4_700
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/threshold.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/threshold.yaml
index 40ca4b1fd92..710c9d84261 100644
--- a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/threshold.yaml
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/high_income/threshold.yaml
@@ -6,11 +6,13 @@ metadata:
   period: year
   label: Arkansas high-income tax table threshold
   uprating:
-    parameter: gov.irs.uprating
+    parameter: gov.states.ar.tax.income.uprating
     rounding:
       type: nearest
       interval: 100
   reference:
+  - title: A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2 (annual CPI-U indexing capped at three percent)
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
   - title: A.C.A. § 26-51-201(a)(4)(A)-(B), as amended by Act 1 of 2026 (1st Extraordinary Session), § 1
     href: https://www.arkleg.state.ar.us/Home/FTPDocument?path=%2FACTS%2F2026S1%2FPublic%2FACT1.pdf#page=1
   - title: A.C.A. § 26-51-201(d)(1), as amended by Act 532 of 2023, § 2 (bracket amounts indexed annually, rounded to the nearest $100)
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/rate.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/rate.yaml
index 4e494618295..8c53dc2aad4 100644
--- a/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/rate.yaml
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/rates/main/rate.yaml
@@ -8,8 +8,8 @@ metadata:
   reference:
   - title: Tax Legislation for 2022 Ark. Code § 26-51-201 (a)(1)(A) # (d)(1) for uprating.
     href: https://law.justia.com/codes/arkansas/title-26/subtitle-5/chapter-51/subchapter-2/section-26-51-201/
-  - title: Arkansas Act 1459 of 2013, § 1 (0.9% first bracket from tax year 2014)
-    href: https://www.arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013R%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=1
+  - title: "Arkansas Act 1459 of 2013, §§ 1-2 (2014 first bracket and capped CPI-U indexing) #page 1,3"
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=1
   - title: Arkansas Act 22 of 2015, § 2, amending Ark. Code § 26-51-201(a) (tax year 2014-2018 tables and the bracket adjustment above $75,000)
     href: https://www.arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2015R%2FPublic%2F&file=22.pdf&ddBienniumSession=2015%2F2015R#page=1
   - title: Arkansas Act 78 of 2017, § 2, amending Ark. Code § 26-51-201(a)(7)-(8) (tax year 2019)
@@ -61,7 +61,7 @@ brackets:
         2014-01-01: 0
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -83,7 +83,7 @@ brackets:
         2026-01-01: 5_600
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -107,7 +107,7 @@ brackets:
         2026-01-01: 11_200
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -131,7 +131,7 @@ brackets:
         2026-01-01: 16_000
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
@@ -156,7 +156,7 @@ brackets:
         2026-01-01: 26_400
       metadata:
         uprating:
-          parameter: gov.irs.uprating
+          parameter: gov.states.ar.tax.income.uprating
           rounding:
             type: nearest
             interval: 100
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/uprating.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/uprating.yaml
new file mode 100644
index 00000000000..2b9be524de4
--- /dev/null
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/uprating.yaml
@@ -0,0 +1,13 @@
+description: Arkansas uses this index to adjust its income tax bracket boundaries for annual increases in the Consumer Price Index for All Urban Consumers, capped at three percent.
+values:
+  # Neutral history supports zero and infinite bounds defined before 2026.
+  2014-01-01: 1
+  # The published 2026 statutory tables anchor subsequent projections.
+  2026-01-01: 1
+metadata:
+  unit: /1
+  label: Arkansas income tax uprating index
+  economy: false
+  reference:
+  - title: A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2 (CPI-U average for twelve months ending August 31, positive increase capped at three percent)
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/uprating_cap.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/uprating_cap.yaml
new file mode 100644
index 00000000000..c1d811a28c8
--- /dev/null
+++ b/policyengine_us/parameters/gov/states/ar/tax/income/uprating_cap.yaml
@@ -0,0 +1,10 @@
+description: Arkansas limits the annual increase in its income tax bracket boundaries to this share.
+values:
+  2014-01-01: 0.03
+metadata:
+  unit: /1
+  period: year
+  label: Arkansas income tax annual uprating cap
+  reference:
+  - title: A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2
+    href: https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
diff --git a/policyengine_us/parameters/gov/states/wv/tax/income/subtractions/senior_citizen_disability_deduction/excluded_income_sources.yaml b/policyengine_us/parameters/gov/states/wv/tax/income/subtractions/senior_citizen_disability_deduction/excluded_income_sources.yaml
index 63c9c52dc00..9d50f180dc4 100644
--- a/policyengine_us/parameters/gov/states/wv/tax/income/subtractions/senior_citizen_disability_deduction/excluded_income_sources.yaml
+++ b/policyengine_us/parameters/gov/states/wv/tax/income/subtractions/senior_citizen_disability_deduction/excluded_income_sources.yaml
@@ -8,10 +8,8 @@ values:
     # Line numbers below are from the 2025 form.
     - military_service_income # Line 36
     - salt_refund_income # Line 38
-    # Line 39 is a contribution deduction, not an income receipt. Its amount
-    # removes income within the form's excluded range. Use the contributor's
-    # own amount rather than projecting the tax-unit 529 deduction to spouses.
-    - investment_in_529_plan_indv # Line 39
+    # Section 11-21-12a separately deducts 529 contribution payments;
+    # those payments are not income excluded from the senior income cap.
 
 metadata:
   unit: list
@@ -26,3 +24,9 @@ metadata:
       href: https://tax.wv.gov/Documents/TaxForms/2018/it140.booklet.pdf#page=5
     - title: West Virginia Personal Income Tax Forms and Instructions 2014, Schedule M line 52
       href: https://tax.wv.gov/Documents/TaxForms/2014/it140.booklet.pdf#page=9
+    - title: W. Va. Code section 11-21-12(c)(9)
+      href: https://code.wvlegislature.gov/11-21-12/
+    - title: W. Va. Code section 11-21-12a, additional college-savings modification
+      href: https://code.wvlegislature.gov/11-21-12a/
+    - title: West Virginia 2000 HB4679, section 11-21-12a
+      href: https://code.wvlegislature.gov/signed_bills/2000/2000-RS-HB4679-SUB%20ENR_signed.pdf#page=3
diff --git a/policyengine_us/parameters/uprating_extensions.py b/policyengine_us/parameters/uprating_extensions.py
index c1c598de334..2b1995b882a 100644
--- a/policyengine_us/parameters/uprating_extensions.py
+++ b/policyengine_us/parameters/uprating_extensions.py
@@ -82,6 +82,45 @@ def get_cpi_u_average_for_12_months_ending_august(
     return get_average_for_12_months_ending_august(parameters.gov.bls.cpi.cpi_u, year)
 
 
+def get_ar_cpi(parameters: ParameterNode, calendar_year: int) -> float:
+    """Average unchained CPI-U for the twelve months ending August 31.
+
+    A.C.A. 26-51-201(d)(2), Act 1459 of 2013, section 2, PDF page 3.
+    For calendar year T this includes September T-1 through August T.
+    """
+    cpi = parameters.gov.bls.cpi.cpi_u
+    start = instant(f"{calendar_year - 1}-09-01")
+    return (
+        sum(cpi(start.offset(month, MONTH)) for month in range(MONTHS_IN_YEAR))
+        / MONTHS_IN_YEAR
+    )
+
+
+def extend_ar_income_tax_uprating(parameters: ParameterNode, end_year: int) -> None:
+    """Compound Arkansas's positive annual CPI-U increase, subject to its cap.
+
+    The published 2026 tables anchor projections. For tax year Y,
+    26-51-201(d)(2) compares September Y-2 through August Y-1 with
+    September Y-3 through August Y-2. The statute's increase-if-any
+    language prevents a decrease. Bracket rounding remains in the
+    individual parameters' metadata, and bracket-adjustment amounts
+    remain fixed.
+    """
+    income = parameters.gov.states.ar.tax.income
+    index = income.uprating
+    for year in range(2027, end_year + 1):
+        current = get_ar_cpi(parameters, year - 1)
+        prior = get_ar_cpi(parameters, year - 2)
+        increase = min(
+            income.uprating_cap(f"{year}-01-01"), max(current / prior - 1, 0)
+        )
+        index.update(
+            period=f"year:{year}-01-01:1",
+            value=index(f"{year - 1}-01-01") * (1 + increase),
+        )
+    index.update(start=instant(f"{end_year}-01-01"), value=index(f"{end_year}-01-01"))
+
+
 def get_or_ctc_cola(parameters: ParameterNode, tax_year: int) -> float:
     """Calculate the Oregon Kids' Credit cost-of-living adjustment.
 
@@ -1018,6 +1057,10 @@ def set_all_uprating_parameters(parameters: ParameterNode) -> ParameterNode:
         period_day=1,
     )
 
+    # Arkansas uses capped positive CPI-U changes over September-August
+    # windows, independently of the shared IRS chained CPI index.
+    extend_ar_income_tax_uprating(parameters, end_year=END_YEAR)
+
     # Chained CPI-U (February values, last projection year 2034)
     extend_parameter_values(
         parameters.gov.bls.cpi.c_cpi_u,
diff --git a/policyengine_us/tests/core/test_state_uprating_rounding.py b/policyengine_us/tests/core/test_state_uprating_rounding.py
index dd11c2cbfdf..187febc0627 100644
--- a/policyengine_us/tests/core/test_state_uprating_rounding.py
+++ b/policyengine_us/tests/core/test_state_uprating_rounding.py
@@ -5,6 +5,9 @@
 import pytest
 
 from policyengine_us.system import system as SYSTEM
+from policyengine_us.tests.fixtures.ar_indexing import (
+    ar_cpi_four_percent_chained_one_percent,
+)
 
 
 def _thresholds(scale, period, bracket_indexes=(1, 2, 3)):
@@ -13,10 +16,11 @@ def _thresholds(scale, period, bracket_indexes=(1, 2, 3)):
 
 def test_ar_income_tax_bounds_round_to_nearest_100_after_last_published_year():
     # A.C.A. 26-51-201(d)(1): bracket amounts are indexed "rounding to the
-    # nearest one hundred dollars ($100)". Expected values follow the loaded
-    # index, so a CPI refresh moves them without breaking the test.
-    main = SYSTEM.parameters.gov.states.ar.tax.income.rates.main
-    uprating = SYSTEM.parameters.gov.irs.uprating
+    # nearest one hundred dollars ($100)". Complete synthetic CPI windows
+    # avoid assuming a resolution for the missing October 2025 observation.
+    parameters = ar_cpi_four_percent_chained_one_percent(SYSTEM).parameters
+    main = parameters.gov.states.ar.tax.income.rates.main
+    uprating = parameters.gov.states.ar.tax.income.uprating
     high_income = main.high_income
     bounds_2026 = {
         "rate": (main.rate, (1, 2, 3, 4), (5_600, 11_200, 16_000, 26_400)),
@@ -43,7 +47,7 @@ def test_ar_income_tax_bounds_round_to_nearest_100_after_last_published_year():
             differs_from_rounding_down |= loaded != rounded_down
         assert isinf(main.rate.brackets[5].threshold(period))
         assert isinf(main.rate.brackets[6].threshold(period))
-    # With 2027's factor, 5,600 x 1.0298 = 5,766.9 rounds up to 5,800.
+    # The synthetic 3% increase takes $5,600 to $5,768, rounded to $5,800.
     assert differs_from_rounding_down
 
 
diff --git a/policyengine_us/tests/core/test_wv_senior_citizen_disability_deduction.py b/policyengine_us/tests/core/test_wv_senior_citizen_disability_deduction.py
index 359eed4a6d0..3a13b5d2841 100644
--- a/policyengine_us/tests/core/test_wv_senior_citizen_disability_deduction.py
+++ b/policyengine_us/tests/core/test_wv_senior_citizen_disability_deduction.py
@@ -1,16 +1,17 @@
 """Hypothesis coverage of Schedule M's person-level subtraction limits.
 
 The 2025 IT-140 Schedule M line 47, boxes (c) and (d), first caps the income
-remaining after lines 35-46 at $8,000, then subtracts the person's own
-lines 29-34 modifications. These properties exercise combinations that the
-worked YAML examples do not enumerate, using the real model and independent
+remaining after the modified income receipts on lines 35-46 at $8,000, then
+subtracts the person's own lines 29-34 modifications. These properties
+exercise combinations that the worked YAML examples do not enumerate,
+using the real model and independent
 conservation and spouse-isolation checks.
 
-The form interpretation includes line 39's deductible 529 contribution in
-the excluded Schedule M amounts: it removes income already deducted on that
-line from the remainder in box (c), although a contribution is not an income
-receipt. Compatibility with the old formula therefore means no excluded
-Schedule M amounts, including no deductible 529 contribution.
+Only income receipts enter the excluded Schedule M amounts. Section
+11-21-12a independently authorizes the line 39 contribution deduction in
+addition to the section 11-21-12(c) modifications. Contributions are outside the income-conservation property below; their
+independence from the senior modification is covered by the variable YAML
+tests.
 
 Fresh two- or four-person simulations reuse the package's reference model;
 they do not share simulation caches, mutate parameters, or load datasets.
@@ -33,7 +34,6 @@
 EXCLUDED_SOURCES = (
     "military_service_income",
     "salt_refund_income",
-    "investment_in_529_plan_indv",
 )
 
 AGIS = st.integers(min_value=-20_000, max_value=60_000)
@@ -44,7 +44,7 @@
 COUPLE = st.tuples(PERSON, PERSON)
 PROPERTY_SETTINGS = settings(max_examples=50, deadline=None, derandomize=True)
 ZERO_MODIFICATIONS = (0, 0, 0, 0)
-ZERO_EXCLUSIONS = (0, 0, 0)
+ZERO_EXCLUSIONS = (0, 0)
 LOW_INCOME_COUPLE = (
     (6_000, ZERO_MODIFICATIONS, ZERO_EXCLUSIONS),
     (6_000, ZERO_MODIFICATIONS, ZERO_EXCLUSIONS),
@@ -118,19 +118,13 @@ def test_without_excluded_amounts_matches_previous_formula(agis, modifications):
 @given(couple=COUPLE)
 @example(
     couple=(
-        (6_000, ZERO_MODIFICATIONS, (0, 2_000, 0)),
+        (6_000, ZERO_MODIFICATIONS, (0, 2_000)),
         (6_000, ZERO_MODIFICATIONS, ZERO_EXCLUSIONS),
     )
 )
 @example(
     couple=(
-        (6_000, ZERO_MODIFICATIONS, (2_000, 0, 0)),
-        (6_000, ZERO_MODIFICATIONS, ZERO_EXCLUSIONS),
-    )
-)
-@example(
-    couple=(
-        (6_000, ZERO_MODIFICATIONS, (0, 0, 2_000)),
+        (6_000, ZERO_MODIFICATIONS, (2_000, 0)),
         (6_000, ZERO_MODIFICATIONS, ZERO_EXCLUSIONS),
     )
 )
@@ -138,8 +132,9 @@ def test_senior_and_other_subtractions_do_not_exceed_income_or_other_subtraction
     couple,
 ):
     deduction = _simulation(couple).calculate(DEDUCTION, YEAR)
-    # Sum each person's independently supplied lines 29-46 amounts, without
-    # using the deduction formula or its intermediate calculated totals.
+    # Sum each person's independently supplied modified income receipts,
+    # without using the deduction formula or its intermediate totals.
+    # A 529 contribution is a payment, so it does not enter this bound.
     subtractions = np.array(
         [
             sum(modifications) + sum(exclusions)
@@ -161,8 +156,6 @@ def test_senior_and_other_subtractions_do_not_exceed_income_or_other_subtraction
 @example(couple=LOW_INCOME_COUPLE, changed_person=1, source_index=0, increase=2_000)
 @example(couple=LOW_INCOME_COUPLE, changed_person=0, source_index=1, increase=2_000)
 @example(couple=LOW_INCOME_COUPLE, changed_person=1, source_index=1, increase=2_000)
-@example(couple=LOW_INCOME_COUPLE, changed_person=0, source_index=2, increase=2_000)
-@example(couple=LOW_INCOME_COUPLE, changed_person=1, source_index=2, increase=2_000)
 def test_changing_one_spouses_excluded_amount_preserves_the_others_modification(
     couple, changed_person, source_index, increase
 ):
diff --git a/policyengine_us/tests/fixtures/ar_indexing.py b/policyengine_us/tests/fixtures/ar_indexing.py
new file mode 100644
index 00000000000..49191846a24
--- /dev/null
+++ b/policyengine_us/tests/fixtures/ar_indexing.py
@@ -0,0 +1,53 @@
+"""Complete synthetic CPI windows for Arkansas indexing mechanism tests."""
+
+from policyengine_core.model_api import Reform
+from policyengine_core.parameters import Parameter
+from policyengine_core.parameters.operations.uprate_parameters import uprate_parameters
+from policyengine_core.periods import instant
+
+from policyengine_us.parameters.uprating_extensions import set_all_uprating_parameters
+
+
+def install_monthly_window(parameter, first_month, value):
+    """Replace all twelve observations, including any missing baseline month."""
+    start = instant(first_month)
+    for month in range(12):
+        parameter.update(period=f"month:{start.offset(month, 'month')}:1", value=value)
+
+
+def _synthetic_indexing(parameters, cpi_u_factor, chained_factor):
+    cpi = parameters.gov.bls.cpi
+    install_monthly_window(cpi.cpi_u, "2024-09-01", 100)
+    install_monthly_window(cpi.cpi_u, "2025-09-01", 100 * cpi_u_factor)
+    # Preserve the shared IRS index's existing August-July window. This
+    # makes its growth intentionally differ from Arkansas's CPI-U growth.
+    install_monthly_window(cpi.c_cpi_u, "2024-08-01", 100)
+    install_monthly_window(cpi.c_cpi_u, "2025-08-01", 100 * chained_factor)
+
+    main = parameters.gov.states.ar.tax.income.rates.main
+    for parameter in main.get_descendants():
+        if isinstance(parameter, Parameter) and parameter.metadata.get("uprating"):
+            parameter.update(
+                start=instant("2026-01-01"),
+                value=parameter("2026-01-01"),
+                remove_after=True,
+            )
+
+    set_all_uprating_parameters(parameters)
+    return uprate_parameters(parameters)
+
+
+def _indexing_reform(cpi_u_factor, chained_factor):
+    class reform(Reform):
+        def apply(self):
+            # Core clones parameters before apply, so mutate that owned tree.
+            self.parameters = _synthetic_indexing(
+                self.parameters, cpi_u_factor, chained_factor
+            )
+
+    return reform
+
+
+ar_cpi_four_percent_chained_one_percent = _indexing_reform(1.04, 1.01)
+ar_cpi_one_percent_chained_four_percent = _indexing_reform(1.01, 1.04)
+ar_cpi_minus_one_percent_chained_four_percent = _indexing_reform(0.99, 1.04)
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_indiv.yaml b/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_indiv.yaml
index b0791e64e0a..7a024de1465 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_indiv.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_indiv.yaml
@@ -541,23 +541,26 @@
     # Midpoint 95,550.50 x 3.9% - 87.40 = 3,639.07 -> 3,639
     ar_income_tax_before_non_refundable_credits_indiv: 3_639
 
-# 2027 cases use incomes whose tax survives a one-step change in the projected
-# uprating factor. The (B)-(C) rows near the indexed threshold (about $97,500)
-# sit within a few hundredths of a percent of a rounding flip, so
-# test_ar_income_tax_schedule.py checks them against the loaded index instead.
-- name: AR 2027 indexed Act 1 of 2026 tables - top of the 0% row
+# These 2027 mechanism tests use complete synthetic CPI-U windows with 4%
+# growth, capped at 3%, and independent chained growth of 1%. They do not
+# assert an actual 2027 coefficient: October 2025 CPI was not published.
+# The synthetic indexed boundaries are $5,800/$11,500/$16,500/$27,200,
+# the high-income threshold is $97,500, and its 2% boundary is $4,800.
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - top of the 0% row
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 5_799
     state_code: AR
   output:
-    # the indexed 2% row starts at $5,800 (5,600 x 1.0298 = 5,767, nearest $100)
+    # The synthetic 2% row starts at $5,800 (5,600 x 1.03 = 5,768, nearest $100).
     ar_income_tax_before_non_refundable_credits_indiv: 0
 
-- name: AR 2027 indexed Act 1 of 2026 tables - 2% row
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - 2% row
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 5_900
     state_code: AR
@@ -565,9 +568,10 @@
     # Row $5,900-$5,999, midpoint 5,949.50: (5,949.50 - 5,800) x 2% = 2.99 -> 3
     ar_income_tax_before_non_refundable_credits_indiv: 3
 
-- name: AR 2027 indexed Act 1 of 2026 tables - income the frozen 2026 reduction undertaxed by $108
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - income the frozen 2026 reduction undertaxed by $108
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 11_300
     state_code: AR
@@ -577,9 +581,10 @@
     # reduction schedule gave 2% x 11,300 - 224 = 2.00
     ar_income_tax_before_non_refundable_credits_indiv: 111
 
-- name: AR 2027 indexed Act 1 of 2026 tables - start of the 3% row
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - start of the 3% row
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 11_500
     state_code: AR
@@ -588,9 +593,10 @@
     # (11,500 - 5,800) x 2% + (11,549.50 - 11,500) x 3% = 114 + 1.485 = 115.485 -> 115
     ar_income_tax_before_non_refundable_credits_indiv: 115
 
-- name: AR 2027 indexed Act 1 of 2026 tables - start of the 3.4% row
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - start of the 3.4% row
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 16_500
     state_code: AR
@@ -599,9 +605,10 @@
     # 114 + (16,500 - 11,500) x 3% + (16,549.50 - 16,500) x 3.4% = 264 + 1.683 = 265.683 -> 266
     ar_income_tax_before_non_refundable_credits_indiv: 266
 
-- name: AR 2027 indexed Act 1 of 2026 tables - income the frozen 2026 reduction undertaxed by $70.20
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - income the frozen 2026 reduction undertaxed by $70.20
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 26_500
     state_code: AR
@@ -611,9 +618,10 @@
     # the frozen 2026 reduction schedule gave 3.4% x 26,500 - 367.20 = 533.80
     ar_income_tax_before_non_refundable_credits_indiv: 606
 
-- name: AR 2027 indexed Act 1 of 2026 tables - start of the 3.7% row
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - start of the 3.7% row
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 27_200
     state_code: AR
@@ -622,21 +630,23 @@
     # 264 + (27,200 - 16,500) x 3.4% + (27,249.50 - 27,200) x 3.7% = 627.80 + 1.8315 = 629.63 -> 630
     ar_income_tax_before_non_refundable_credits_indiv: 630
 
-- name: AR 2027 indexed Act 1 of 2026 tables - top of table (A) at the indexed high-income threshold
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - top of table (A) at the indexed high-income threshold
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 97_500
     state_code: AR
   output:
-    # The threshold is 94,700 x 1.0298 = 97,522, nearest $100 = 97,500. Row
+    # The synthetic threshold is 94,700 x 1.03 = 97,541, nearest $100 = 97,500. Row
     # $97,401-$97,500, midpoint 97,450.50 <= 97,500, so table (A):
     # 627.80 + (97,450.50 - 27,200) x 3.7% = 627.80 + 2,599.27 = 3,227.07 -> 3,227
     ar_income_tax_before_non_refundable_credits_indiv: 3_227
 
-- name: AR 2027 indexed Act 1 of 2026 tables - high income
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - high income
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_indiv: 150_000
     state_code: AR
@@ -797,3 +807,40 @@
   output:
     # "For $50,000 and over" (p.6): 50,000 x 7% - 949.24 = 2,550.76
     ar_income_tax_before_non_refundable_credits_indiv: 2_550.76
+
+# A.C.A. § 26-51-201(d)(2), Act 1459 of 2013, § 2, PDF page 3:
+# https://arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2013%2FPublic%2F&file=1459.pdf&ddBienniumSession=2013%2F2013R#page=3
+# These complete synthetic windows test the indexing rule, not an actual
+# 2027 coefficient: the October 2025 CPI observation was not published.
+- name: Arkansas caps synthetic four percent CPI-U growth at three percent
+  period: 2027
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
+  input:
+    state_code: AR
+    ar_taxable_income_indiv: 150_000
+  output:
+    # $4,700 * 1.03 rounds to $4,800; $96 + $145,200 * 3.7%.
+    ar_income_tax_before_non_refundable_credits_indiv: 5_468.40
+
+- name: Arkansas uses synthetic CPI-U growth rather than chained growth
+  period: 2027
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_one_percent_chained_four_percent
+  input:
+    state_code: AR
+    ar_taxable_income_indiv: 150_000
+  output:
+    # $4,700 * 1.01 rounds to $4,700; $94 + $145,300 * 3.7%.
+    ar_income_tax_before_non_refundable_credits_indiv: 5_470.10
+
+- name: Arkansas does not lower boundaries after a synthetic CPI-U decrease
+  period: 2027
+  absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_minus_one_percent_chained_four_percent
+  input:
+    state_code: AR
+    ar_taxable_income_indiv: 150_000
+  output:
+    # Negative CPI-U growth leaves the $4,700 boundary unchanged.
+    ar_income_tax_before_non_refundable_credits_indiv: 5_470.10
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_joint.yaml b/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_joint.yaml
index 973c835dbc3..24546ff9518 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_joint.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/ar/tax/income/ar_income_tax_before_non_refundable_credits_joint.yaml
@@ -208,15 +208,18 @@
     # 2024 published last row $35,001-$35,100 -> $765
     ar_income_tax_before_non_refundable_credits_joint: [765, 0, 0, 0]
 
-- name: AR 2027 indexed Act 1 of 2026 tables - joint return above the low-income tables
+- name: AR 2027 synthetic indexed Act 1 of 2026 tables - joint return above the low-income tables
   period: 2027
   absolute_error_margin: 0.01
+  reforms: policyengine_us.tests.fixtures.ar_indexing.ar_cpi_four_percent_chained_one_percent
   input:
     ar_taxable_income_joint: 50_000
     ar_low_income_tax_joint: 5_000
     state_code: AR
   output:
-    # Indexed 2027 rows start at 5,800 / 11,500 / 16,500 / 27,200 (nearest $100).
+    # Complete synthetic CPI-U windows grow 4%, capped at 3%, while chained
+    # growth is 1%. These rows do not assert an actual 2027 CPI coefficient.
+    # Synthetic rows start at 5,800 / 11,500 / 16,500 / 27,200 (nearest $100).
     # Table row $50,000-$50,099, midpoint 50,049.50:
     # 5,700 x 2% + 5,000 x 3% + 10,700 x 3.4% + (50,049.50 - 27,200) x 3.7%
     # = 627.80 + 845.43 = 1,473.23 -> 1,473
diff --git a/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/credits/dependent_care_credit/ky_cdcc.yaml b/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/credits/dependent_care_credit/ky_cdcc.yaml
index 0c2c44f6451..ada3807fa50 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/credits/dependent_care_credit/ky_cdcc.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/ky/tax/income/credits/dependent_care_credit/ky_cdcc.yaml
@@ -247,3 +247,328 @@
   output:
     cdcc: 200
     ky_cdcc_potential: 40
+
+# Kentucky's December 31, 2018 IRC reference excludes ARPA's 2021 expansion.
+# 2021 Ky. Acts ch. 31, section 1 (KRS 141.010(21)(b)), PDF page 3:
+# https://apps.legislature.ky.gov/law/acts/21RS/documents/0031.pdf#page=3
+# Form 2441-K pages 1-3 confirms the conformed cap, rate, benefits, and
+# federal liability limit before Kentucky's 20% match:
+# https://revenue.ky.gov/Forms/2441-K-2021.pdf#page=1
+
+- name: 2021 Kentucky retains the pre-ARPA expense cap and rate
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 10_000
+    care_expenses: 0
+    min_head_spouse_earned: 50_000
+    dependent_care_employer_benefits: 0
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% match x 20% rate x $6,000 conformed expense cap.
+    ky_cdcc_potential: 240
+    # The federal ARPA calculation continues to use 50% of $10,000.
+    cdcc: 5_000
+
+- name: 2021 Kentucky does not import federal CDCC refundability
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 10_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    care_expenses: 0
+    min_head_spouse_earned: 10_000
+    dependent_care_employer_benefits: 0
+    cdcc_credit_limit: 0
+  output:
+    # Kentucky matches min(35% x $3,000, $0), while federal ARPA is refundable.
+    ky_cdcc_potential: 0
+    cdcc: 1_500
+
+- name: 2021 Kentucky retains credit after ARPA's high-income phaseout
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 450_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    care_expenses: 0
+    min_head_spouse_earned: 450_000
+    dependent_care_employer_benefits: 0
+    cdcc_credit_limit: 100_000
+  output:
+    # The conformed 20% rate has no second phaseout: 20% x 20% x $3,000.
+    ky_cdcc_potential: 120
+    cdcc: 0
+
+- name: 2021 Kentucky applies the federal liability limit before its match
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 6_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 500
+  output:
+    # 20% x min(20% x $6,000, $500).
+    ky_cdcc_potential: 100
+
+- name: 2021 Kentucky retains the pre-ARPA dependent-care benefit exclusion cap
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: JOINT
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 10_000
+    min_head_spouse_earned: 25_000
+    dependent_care_employer_benefits: 6_000
+    cdcc_credit_limit: 5_000
+  output:
+    # Exclusion=min($6,000,$5,000)=$5,000; remaining cap=$1,000.
+    # 20% match x 20% rate x min($10,000-$5,000,$6,000-$5,000).
+    ky_cdcc_potential: 40
+
+- name: 2021 Kentucky excludes reimbursed expenses below the remaining cap
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    dependent_care_employer_benefits: 1_000
+    cdcc_credit_limit: 5_000
+  output:
+    # Expenses=$3,000-$1,000=$2,000, below the $5,000 remaining cap.
+    ky_cdcc_potential: 80
+
+- name: 2021 Kentucky limits the benefit exclusion to earned income
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: JOINT
+    adjusted_gross_income: 10_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 2_000
+    dependent_care_employer_benefits: 5_000
+    cdcc_credit_limit: 5_000
+  output:
+    # Exclusion=min($5,000,$5,000,$2,000,$3,000)=$2,000.
+    # 20% match x 35% rate x min($3,000-$2,000,$3,000-$2,000,$2,000).
+    ky_cdcc_potential: 70
+
+- name: 2021 Kentucky caps expenses at the lesser of the spouses' earnings
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: JOINT
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 6_000
+    min_head_spouse_earned: 1_000
+    cdcc_credit_limit: 5_000
+  output:
+    ky_cdcc_potential: 40
+
+- name: 2021 Kentucky excludes separate filers not treated as unmarried
+  period: 2021
+  input:
+    state_code: KY
+    filing_status: SEPARATE
+    cdcc_treated_as_unmarried: false
+    adjusted_gross_income: 50_000
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 6_000
+    min_head_spouse_earned: 50_000
+    dependent_care_employer_benefits: 1_000
+    cdcc_credit_limit: 5_000
+  output:
+    ky_cdcc_potential: 0
+
+- name: 2021 Kentucky uses the unmarried benefit cap for a qualifying separate filer
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SEPARATE
+    cdcc_treated_as_unmarried: true
+    adjusted_gross_income: 50_000
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 8_000
+    min_head_spouse_earned: 50_000
+    dependent_care_employer_benefits: 4_000
+    cdcc_credit_limit: 5_000
+  output:
+    # The full $4,000 is excluded, leaving a $2,000 creditable expense cap.
+    ky_cdcc_potential: 80
+
+- name: 2021 Kentucky includes care expenses for a qualifying adult
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 0
+    care_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    ky_cdcc_potential: 120
+
+- name: 2021 Kentucky rate boundary at AGI 15,000 is 35 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 15_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 35% conformed rate.
+    ky_cdcc_potential: 210
+
+- name: 2021 Kentucky rate boundary at AGI 15,001 is 34 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 15_001
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 34% conformed rate.
+    ky_cdcc_potential: 204
+
+- name: 2021 Kentucky rate boundary at AGI 17,000 is 34 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 17_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 34% conformed rate.
+    ky_cdcc_potential: 204
+
+- name: 2021 Kentucky rate boundary at AGI 17,001 is 33 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 17_001
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 33% conformed rate.
+    ky_cdcc_potential: 198
+
+- name: 2021 Kentucky rate boundary at AGI 43,000 is 21 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 43_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 21% conformed rate.
+    ky_cdcc_potential: 126
+
+- name: 2021 Kentucky rate boundary at AGI 43,001 is 20 percent
+  period: 2021
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 43_001
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 1
+    cdcc_qualifying_childcare_expenses: 3_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    # 20% Kentucky match x $3,000 expenses x 20% conformed rate.
+    ky_cdcc_potential: 120
+
+- name: 2020 Kentucky preserves the federal credit computation
+  period: 2020
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 10_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    cdcc: 1_200
+    ky_cdcc_potential: 240
+
+- name: 2022 Kentucky preserves the federal credit computation
+  period: 2022
+  absolute_error_margin: 0.01
+  input:
+    state_code: KY
+    filing_status: SINGLE
+    adjusted_gross_income: 50_000
+    cdcc_filing_status_eligible: true
+    capped_count_cdcc_eligible: 2
+    cdcc_qualifying_childcare_expenses: 10_000
+    min_head_spouse_earned: 50_000
+    cdcc_credit_limit: 5_000
+  output:
+    cdcc: 1_200
+    ky_cdcc_potential: 240
diff --git a/policyengine_us/tests/policy/baseline/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.yaml b/policyengine_us/tests/policy/baseline/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.yaml
index 0db631f2408..4a5445d7194 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.yaml
@@ -142,7 +142,7 @@
     wv_senior_citizen_disability_deduction: 10_000
     wv_subtractions: 12_000
 
-- name: A line 39 contribution reduces only the contributor's remaining income.
+- name: A 529 contribution preserves both spouses' senior modifications.
   period: 2025
   input:
     people:
@@ -164,11 +164,11 @@
         members: [head, spouse]
         state_code: WV
   output:
-    # The contribution deducts 2,000 on a line within the excluded range.
-    # Head: min(6,000 - 2,000, 8,000); spouse: min(6,000, 8,000).
+    # Section 11-21-12a allows the contribution in addition to both
+    # senior modifications: 6,000 + 6,000 + 2,000 = 14,000.
     wv_529_plan_deduction: 2_000
-    wv_senior_citizen_disability_deduction_person: [4_000, 6_000]
-    wv_subtractions: 12_000
+    wv_senior_citizen_disability_deduction_person: [6_000, 6_000]
+    wv_subtractions: 14_000
 
 - name: Income still above the cap after exclusions leaves the modification unchanged.
   period: 2025
@@ -181,7 +181,7 @@
     wv_senior_citizen_disability_deduction_total_modifications: 3_000
     state_code: WV
   output:
-    # min(20,000 - 4,000, 8,000) - 3,000 = 5,000, as before.
+    # min(20,000 - 3,000, 8,000) - 3,000 = 5,000, as before.
     wv_senior_citizen_disability_deduction_person: 5_000
 
 - name: Box d is subtracted after excluding refunds and applying the cap.
@@ -231,7 +231,7 @@
   output:
     wv_senior_citizen_disability_deduction_person: 0
 
-- name: A qualifying disabled person also excludes a line 39 contribution.
+- name: A qualifying disabled person retains the additional 529 deduction.
   period: 2025
   input:
     age: 50
@@ -240,10 +240,10 @@
     investment_in_529_plan_indv: 1_000
     state_code: WV
   output:
-    # min(6,000 - 1,000, 8,000) - 0 = 5,000.
-    wv_senior_citizen_disability_deduction_person: 5_000
+    # min(6,000, 8,000) - 0 = 6,000, plus the separate contribution.
+    wv_senior_citizen_disability_deduction_person: 6_000
     wv_529_plan_deduction: 1_000
-    wv_subtractions: 6_000
+    wv_subtractions: 7_000
 
 - name: Each spouse's $8,000 limit uses their own AGI, after their own IRA deduction.
   period: 2024
@@ -268,3 +268,71 @@
     # W. Va. Code 11-21-12(c): up to $8,000 of each eligible individual's
     # federal AGI. Before: [5_000, 8_000].
     wv_senior_citizen_disability_deduction_person: [4_000, 8_000]
+
+# W. Va. Code sections 11-21-12(c)(9) and 11-21-12a: contribution payments
+# are deductible separately, rather than income excluded from box (c).
+- name: A senior's contribution does not reduce the senior modification.
+  period: 2025
+  input:
+    state_code: WV
+    age: 66
+    is_tax_unit_head: true
+    adjusted_gross_income_person: 6_000
+    investment_in_529_plan_indv: 2_000
+    wv_senior_citizen_disability_deduction_total_modifications: 0
+  output:
+    wv_senior_citizen_disability_deduction_person: 6_000
+    wv_529_plan_deduction: 2_000
+
+- name: The 529 contribution is independent from the senior income cap from 2014.
+  period: 2014
+  input:
+    wv_senior_citizen_disability_deduction_eligible_person: true
+    adjusted_gross_income_person: 6_000
+    investment_in_529_plan_indv: 2_000
+    wv_senior_citizen_disability_deduction_total_modifications: 0
+  output:
+    wv_senior_citizen_disability_deduction_person: 6_000
+
+- name: Refund exclusions and modifications still apply independently of contributions.
+  period: 2025
+  input:
+    state_code: WV
+    age: 66
+    adjusted_gross_income_person: 6_000
+    investment_in_529_plan_indv: 2_000
+    salt_refund_income: 1_000
+    wv_senior_citizen_disability_deduction_total_modifications: 500
+  output:
+    # Preserve Schedule M base: min(6,000 - 1,000, 8,000) - 500.
+    wv_senior_citizen_disability_deduction_person: 4_500
+
+- name: A senior's additional 529 deduction remains available on a joint return.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 66
+        adjusted_gross_income_person: 6_000
+        investment_in_529_plan_indv: 2_000
+        wv_senior_citizen_disability_deduction_total_modifications: 0
+      spouse:
+        age: 60
+        adjusted_gross_income_person: 40_000
+    tax_units:
+      unit:
+        members: [head, spouse]
+        filing_status: JOINT
+        adjusted_gross_income: 46_000
+        wv_additions: 0
+        wv_low_income_earned_income_exclusion: 0
+    households:
+      household:
+        members: [head, spouse]
+        state_code: WV
+  output:
+    wv_senior_citizen_disability_deduction_person: [6_000, 0]
+    wv_529_plan_deduction: 2_000
+    wv_subtractions: 8_000
+    wv_agi: 38_000
+    wv_taxable_income: 34_000
diff --git a/policyengine_us/tests/test_ar_income_tax_indexing.py b/policyengine_us/tests/test_ar_income_tax_indexing.py
new file mode 100644
index 00000000000..16300eb7428
--- /dev/null
+++ b/policyengine_us/tests/test_ar_income_tax_indexing.py
@@ -0,0 +1,122 @@
+"""Arkansas's statutory CPI-U window, cap, floor, and annual compounding."""
+
+import pytest
+from policyengine_core.parameters import ParameterNode
+from policyengine_core.periods import instant
+
+from policyengine_us.parameters.uprating_extensions import (
+    extend_ar_income_tax_uprating,
+    get_ar_cpi,
+)
+from policyengine_us.system import system
+from policyengine_us.tests.fixtures.ar_indexing import (
+    ar_cpi_four_percent_chained_one_percent,
+)
+
+
+def synthetic_parameters(annual_levels):
+    monthly = {}
+    for offset, level in enumerate(annual_levels):
+        start = instant(f"{2024 + offset}-09-01")
+        for month in range(12):
+            monthly[str(start.offset(month, "month"))] = level
+    return ParameterNode(
+        data={
+            "gov": {
+                "bls": {"cpi": {"cpi_u": {"values": monthly}}},
+                "states": {
+                    "ar": {
+                        "tax": {
+                            "income": {
+                                "uprating": {"values": {"2026-01-01": 1}},
+                                "uprating_cap": {"values": {"2014-01-01": 0.03}},
+                            }
+                        }
+                    }
+                },
+            }
+        }
+    )
+
+
+@pytest.fixture(scope="module")
+def capped_parameters():
+    """Read-only reformed parameters shared by the Core integration checks."""
+    return ar_cpi_four_percent_chained_one_percent(system).parameters
+
+
+def test_ar_cpi_averages_september_through_august():
+    parameters = synthetic_parameters((100, 100))
+    cpi = parameters.gov.bls.cpi.cpi_u
+    # An IRS-style August-July window would include the first poison month
+    # and miss August 2026. The following September must also be excluded.
+    cpi.update(period="month:2024-08-01:1", value=200)
+    cpi.update(period="month:2026-08-01:1", value=124)
+    cpi.update(period="month:2026-09-01:1", value=500)
+
+    assert get_ar_cpi(parameters, 2025) == pytest.approx(100)
+    assert get_ar_cpi(parameters, 2026) == pytest.approx(102)
+    extend_ar_income_tax_uprating(parameters, end_year=2027)
+    assert parameters.gov.states.ar.tax.income.uprating("2027-01-01") == pytest.approx(
+        1.02
+    )
+
+
+@pytest.mark.parametrize(
+    "current_level, expected_index",
+    ((99, 1), (100, 1), (101, 1.01), (103, 1.03), (104, 1.03)),
+)
+def test_ar_index_applies_the_increase_if_any_and_cap(current_level, expected_index):
+    parameters = synthetic_parameters((100, current_level))
+
+    extend_ar_income_tax_uprating(parameters, end_year=2027)
+
+    assert parameters.gov.states.ar.tax.income.uprating("2027-01-01") == pytest.approx(
+        expected_index
+    )
+
+
+def test_ar_index_compounds_each_year_from_the_preceding_index():
+    parameters = synthetic_parameters((100, 104, 106.08))
+
+    extend_ar_income_tax_uprating(parameters, end_year=2028)
+
+    index = parameters.gov.states.ar.tax.income.uprating
+    assert index("2026-01-01") == 1
+    assert index("2027-01-01") == pytest.approx(1.03)
+    # Four percent is capped in 2027, then two percent compounds in 2028.
+    assert index("2028-01-01") == pytest.approx(1.03 * 1.02)
+    assert index("2029-01-01") == pytest.approx(index("2028-01-01"))
+
+
+def test_ar_index_and_irs_index_remain_independent(capped_parameters):
+    ar_index = capped_parameters.gov.states.ar.tax.income.uprating
+    irs_index = capped_parameters.gov.irs.uprating
+
+    assert ar_index("2027-01-01") / ar_index("2026-01-01") == pytest.approx(1.03)
+    assert irs_index("2027-01-01") / irs_index("2026-01-01") == pytest.approx(1.01)
+
+
+def test_ar_published_tables_and_fixed_bracket_adjustments_are_preserved(
+    capped_parameters,
+):
+    original = system.parameters.gov.states.ar.tax.income.rates.main
+    reformed = capped_parameters.gov.states.ar.tax.income.rates.main
+
+    for year in range(2014, 2027):
+        period = f"{year}-01-01"
+        assert [b.threshold(period) for b in reformed.rate.brackets] == [
+            b.threshold(period) for b in original.rate.brackets
+        ]
+    assert [b.threshold("2026-01-01") for b in reformed.rate.brackets[1:5]] == [
+        5_600,
+        11_200,
+        16_000,
+        26_400,
+    ]
+    assert reformed.high_income.threshold("2026-01-01") == 94_700
+    assert reformed.high_income.threshold("2027-01-01") == 97_500
+    assert reformed.high_income.rate.brackets[1].threshold("2027-01-01") == 4_800
+    assert [
+        b.amount("2027-01-01") for b in reformed.high_income.bracket_adjustment.brackets
+    ] == list(range(290, -1, -10))
diff --git a/policyengine_us/tests/test_ar_income_tax_schedule.py b/policyengine_us/tests/test_ar_income_tax_schedule.py
index 3e3bd69e314..342b24029c2 100644
--- a/policyengine_us/tests/test_ar_income_tax_schedule.py
+++ b/policyengine_us/tests/test_ar_income_tax_schedule.py
@@ -27,7 +27,7 @@
   row's start is skipped.
 - 2026: Act 1 of 2026 (1st Extraordinary Session), A.C.A. 26-51-201(a)(4).
 - 2027-2035: Act 1 of 2026's tables with every bracket bound indexed from
-  2026 by PolicyEngine's uprating index and rounded to the nearest $100.
+  2026 by Arkansas's capped CPI-U index and rounded to the nearest $100.
 
 Invariants:
 - reduction.yaml rows carry strictly increasing finite thresholds, with every
@@ -66,7 +66,7 @@
 )
 
 P = system.parameters.gov.states.ar.tax.income.rates.main
-UPRATING = system.parameters.gov.irs.uprating
+UPRATING = system.parameters.gov.states.ar.tax.income.uprating
 PUBLISHED_YEARS = range(2021, 2026)
 SOURCE_YEARS = range(2021, 2036)
 LONG_RUN_YEARS = [2050, 2075, 2100]
@@ -188,7 +188,9 @@ def act_1_of_2026_tax(ti):
 
 def nearest_100(amount):
     # 26-51-201(d)(1): "rounding to the nearest one hundred dollars ($100)".
-    return np.floor(amount / 100 + 0.5) * 100
+    # Preserve Core's existing ties-to-even convention for exact $50 ties;
+    # the statute does not specify a tie-breaking rule.
+    return round(amount / 100) * 100
 
 
 def indexed_act_1_of_2026_tax(year, ti):
diff --git a/policyengine_us/variables/gov/states/ky/tax/income/credits/dependent_care_service/ky_cdcc_potential.py b/policyengine_us/variables/gov/states/ky/tax/income/credits/dependent_care_service/ky_cdcc_potential.py
index 73f62508423..c708cea4a3e 100644
--- a/policyengine_us/variables/gov/states/ky/tax/income/credits/dependent_care_service/ky_cdcc_potential.py
+++ b/policyengine_us/variables/gov/states/ky/tax/income/credits/dependent_care_service/ky_cdcc_potential.py
@@ -5,11 +5,28 @@ class ky_cdcc_potential(Variable):
     value_type = float
     entity = TaxUnit
     label = "Kentucky household and dependent care service credit"
+    documentation = (
+        "Kentucky matches the federal credit allowed under its conformed "
+        "Internal Revenue Code. For 2021, the December 31, 2018 reference "
+        "excludes ARPA's expanded expense limits, rates, benefit exclusion "
+        "and refundability. The credit is recomputed under that Code before "
+        "applying Kentucky's match."
+    )
     unit = USD
     definition_period = YEAR
     reference = (
         "https://apps.legislature.ky.gov/law/statutes/statute.aspx?id=29058",
         "https://apps.legislature.ky.gov/law/statutes/statute.aspx?id=57913#page=3",
+        # 2021 KRS 141.010(21)(b): December 31, 2018 conformity.
+        "https://apps.legislature.ky.gov/law/acts/21RS/documents/0031.pdf#page=3",
+        # The 2022 amendment advances conformity for taxable years from 2022.
+        "https://apps.legislature.ky.gov/law/acts/22RS/documents/0212.pdf#page=62",
+        # PDF pages 1-3: IRC 21(a)-(d) cap, rate, earnings limits, and
+        # amendment history confirming these provisions were unchanged in 2018.
+        "https://www.govinfo.gov/content/pkg/USCODE-2020-title26/pdf/USCODE-2020-title26-subtitleA-chap1-subchapA-partIV-subpartA-sec21.pdf#page=1",
+        # PDF pages 1-3: conformed credit computation, section 129 benefit
+        # reconciliation, and federal liability limit; instructions exclude ARPA.
+        "https://revenue.ky.gov/Forms/2441-K-2021.pdf#page=1",
     )
     defined_for = StateCode.KY
 
@@ -21,12 +38,63 @@ def formula(tax_unit, period, parameters):
         # date. Where the reference date predates the One Big Beautiful Bill
         # Act, Kentucky's section 21 excludes the Act's rate increase. From
         # 2026 the reference date is December 31, 2025, which includes it.
-        # The 2019-2021 reference date (December 31, 2018) also excludes the
-        # American Rescue Plan Act's 2021 section 21 expansion (2021 Form
-        # 2441-K); the model does not apply that yet, so 2021 reads the live
-        # federal credit.
         if p.irc_conformity.obbba:
             federal_credit = tax_unit("cdcc", period)
         else:
             federal_credit = tax_unit("pre_obbba_cdcc", period)
         return federal_credit * p.credits.dependent_care_service.match
+
+    def formula_2021_01_01(tax_unit, period, parameters):
+        # The December 31, 2018 Code excludes both ARPA's section 21 expansion
+        # and section 129 exclusion increase. The 2020 parameters preserve
+        # these unchanged pre-ARPA provisions without changing federal 2021.
+        frozen = parameters("2020-01-01").gov.irs
+        p = frozen.credits.cdcc
+        childcare = tax_unit("cdcc_qualifying_childcare_expenses", period)
+        adult_care = add(tax_unit, period, ["care_expenses"])
+        expenses = max_(childcare + adult_care, 0)
+        earnings = max_(tax_unit("min_head_spouse_earned", period), 0)
+
+        # Form 2441-K Part III lines 18-29 limit excluded/deductible benefits
+        # to benefits received, qualifying expenses, earnings, and $5,000
+        # ($2,500 for a married separate filer not treated as unmarried).
+        benefits = max_(add(tax_unit, period, ["dependent_care_employer_benefits"]), 0)
+        exclusion_caps = frozen.gross_income.dependent_care_assistance_programs
+        filing_status = tax_unit("filing_status", period)
+        treated_as_unmarried = tax_unit("cdcc_treated_as_unmarried", period)
+        exclusion_cap = where(
+            treated_as_unmarried,
+            exclusion_caps.reduction_amount["SINGLE"],
+            exclusion_caps.reduction_amount[filing_status],
+        )
+        exclusion = min_(benefits, min_(expenses, min_(earnings, exclusion_cap)))
+
+        # Lines 28-32 reduce both the conformed $3,000/$6,000 expense cap
+        # and qualified expenses by these excluded/deductible benefits.
+        qualifying_count = min_(
+            tax_unit("capped_count_cdcc_eligible", period), p.eligibility.max
+        )
+        expense_limit = max_(p.max * qualifying_count - exclusion, 0)
+        creditable_expenses = min_(
+            expense_limit, min_(max_(expenses - exclusion, 0), earnings)
+        )
+
+        # Part II line 8: 35%, less one point for every started $2,000 over
+        # $15,000, floored at 20%. The conformed Code has no second phaseout.
+        agi = tax_unit("adjusted_gross_income", period)
+        increments = np.ceil(max_(agi - p.phase_out.start, 0) / p.phase_out.increment)
+        rate = max_(p.phase_out.min, p.phase_out.max - increments * p.phase_out.rate)
+        eligible = tax_unit("cdcc_filing_status_eligible", period)
+        potential = eligible * creditable_expenses * rate
+        # Part II lines 10-12: apply the federal liability limit first, then
+        # Kentucky's 20% match. ARPA's federal refundability does not apply.
+        federal_credit = min_(potential, tax_unit("cdcc_credit_limit", period))
+        match = parameters(
+            period
+        ).gov.states.ky.tax.income.credits.dependent_care_service.match
+        return federal_credit * match
+
+    def formula_2022_01_01(tax_unit, period, parameters):
+        # ARPA's temporary expansion has ended; retain the ordinary
+        # computation and subsequent conformity changes from 2022 onward.
+        return ky_cdcc_potential.formula(tax_unit, period, parameters)
diff --git a/policyengine_us/variables/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.py b/policyengine_us/variables/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.py
index a13eabbf8cb..5a55696ff95 100644
--- a/policyengine_us/variables/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.py
+++ b/policyengine_us/variables/gov/states/wv/tax/income/subtractions/senior_citizen_disability/wv_senior_citizen_disability_deduction_person.py
@@ -9,6 +9,7 @@ class wv_senior_citizen_disability_deduction_person(Variable):
     definition_period = YEAR
     reference = (
         "https://code.wvlegislature.gov/11-21-12/",
+        "https://code.wvlegislature.gov/11-21-12a/",
         "https://tax.wv.gov/Documents/PIT/2025/it140.PersonalIncomeTaxFormsAndInstructions.2025.pdf#page=6",
         "https://tax.wv.gov/Documents/PIT/2024/it140.PersonalIncomeTaxFormsAndInstructions.2024.pdf#page=6",
         "https://tax.wv.gov/Documents/TaxForms/2018/it140.booklet.pdf#page=5",
@@ -21,8 +22,9 @@ def formula(person, period, parameters):
         ).gov.states.wv.tax.income.subtractions.senior_citizen_disability_deduction
 
         agi_person = person("adjusted_gross_income_person", period)
-        # Box (c) excludes the person's own amounts on lines 35-46 before
-        # applying the cap, including income already deducted on line 39.
+        # Box (c) excludes the person's own modified income receipts on
+        # lines 35-46 before applying the cap. The separate section 12a
+        # deduction for 529 contribution payments does not exclude income.
         excluded_amounts = add(person, period, p.excluded_income_sources)
         capped_income = min_(p.cap, agi_person - excluded_amounts)
         # Box (d) then subtracts the person's own lines 29-34 modifications.