DC TANF benefit computation: applicant disregards for new eligible units, child care deducted from unearned income, and no rounding down (ESA Policy Manual §§ 6.3, 8.5) #10488

Problem

Three DC TANF benefit-computation rules in the ESA Policy Manual are not modeled. All three are pre-existing on main.

1. Benefit level for applicants. Part VI, § 6.3 (PDF page 296): "when determining level of benefits, recipient disregards are always used, even for new cases. Applicant disregards are only used to determine initial eligibility for new applicants." D.C. Code § 4-205.11(a)(4A)(A) also applies the percentage disregard to "individuals otherwise found eligible to receive TANF". dc_tanf_earned_income_after_disregard_person returns where(enrolled, <$160 and two thirds>, <$160 only>), and dc_tanf uses the same countable income. So an eligible unit that is not enrolled is paid on the $160-only figure. This is the same pattern as NH FANF in New Hampshire FANF: recipient_rate gives every recipient the 75% Cliff Effect pilot disregard from September 2022; He-W 654.13(e) and FAM 603.01 set 50% #9984.
2. Child care deduction. § 6.3 (PDF page 297): "Child care costs can only be subtracted from earned income. [...] No deductions to unearned income can be made based on child care or work expenses." dc_tanf_countable_income subtracts dc_tanf_childcare_deduction from earned plus unearned income.
3. Rounding. § 8.5 (PDF page 328): "Subtract net countable income from the appropriate Payment Level for the appropriate group size. Round the result to the next lowest whole dollar." dc_tanf is not floored.

Fix

1. Use the applicant ($160-only) figure for the initial eligibility test only, and the recipient figure ($160, then two thirds) for the benefit amount of every eligible unit.
2. Cap the child care deduction at net earned income.
3. Floor the monthly benefit to whole dollars.

dc_power and dc_gac read the same countable income, so check them too.

Test case (ESA Manual worked example, PDF page 328): gross earned income $537.50 and $150 of Social Security give net countable income $275.83 (537.50 − 160 = 377.50; 377.50 − 251.67 = 125.83; 125.83 + 150). With a $528 payment level, the benefit is $252.17, rounded down to $252.

Found in DTrim99's review of #10250 (suggestion 4).