Fix Indiana TANF to pay the maximum benefit (IC 12-14-2-5)

[hua7450]

Summary

Fixes #7855

Indiana TANF was paying the standard of need ($255 for a family of two) instead of the amount of assistance / maximum benefit ($409). This corrects the benefit to the IC 12-14-2-5 maximum benefit and adds the post-2025 income eligibility screens. For a zero-income family of two the modeled benefit goes from $255 to $409, effective 2025-07-01.

Regulatory authority

• IC 12-14-2-5 (amount of assistance; payment made; maximum amounts) — payment schedule of $248 / $409 / +$104 per additional member (added by SEA 265 / P.L.103-2023).
• IC 12-14-1-1.7 — post-2025 gross income eligibility: 35% FPL through June 30, 2027, then 50% FPL.
• FSSA SNAP/TANF Program Policy Manual, Chapter 3000 — §3050.10.00 (maximum benefits; current chart labeled effective 7/1/2025), §3010.15.00 (initial gross/net standards), §3010.15.05 (100% FPL continuing standard).
• FSSA SNAP/TANF Transmittal 2024 — maximum benefits updated effective 7/1/2024.

What changed

New parameters (gov/states/in/fssa/tanf/):

• amount_of_assistance/amount.yaml — maximum benefit by unit size, tiers at 1997-10-01, 2023-07-01, and 2025-07-01 ($248/$409/$513/.../$1,241).
• amount_of_assistance/max_table_size.yaml (10) + additional_member_amount.yaml ($104 from 2025-07-01) for units above size 10.
• eligibility/initial/gross_income/fpg_rate.yaml (35% from 2025-07-01, 50% from 2027-07-01) and eligibility/initial/net_income/maximum_grant_rate.yaml (100% of the maximum grant from 2025-07-01).

New variables: in_tanf_maximum_benefit, in_tanf_gross_income, in_tanf_fpg, in_tanf_initial_gross_income_standard.

Updated variables: in_tanf and in_tanf_payment_eligible now use the maximum benefit; in_tanf_countable_income_eligible applies the post-2025 gross + net initial screens while preserving the pre-2025 standard-of-need test and the 100% FPL continuing test. in_tanf_payment_standard (standard of need) is unchanged apart from a period.this_year alignment on the size lookup.

Behavior

• Zero-income family of two: $255 (Jan 2024 and Jan 2025, still the 2023-07 tier) → $409 (from July 2025). Pre-July-2025 and historical amounts unchanged.
• The 2025-07-01 increase also widens payment eligibility (income between the old standard of need and the new maximum grant now yields a benefit).
• Post-2025 initial applicants are screened on gross income (below 35%/50% FPL) and countable net income (below the maximum grant); enrolled recipients keep the 100% FPL test. Comparisons use the FSSA §3010.15.00 "less than" wording (strict <). For Indiana the net (maximum-grant) standard binds before the looser gross screen.

Test plan

• New in_tanf_maximum_benefit.yaml, in_tanf_gross_income.yaml, in_tanf_fpg.yaml, and in_tanf_initial_gross_income_standard.yaml; expanded in_tanf, payment-eligibility, countable-income-eligibility, integration, and edge-case tests covering the 2023/2025 increases, the post-2025 screens, the size-10 / size-11 boundary, and the negative-income benefit cap.
• Mid-year transitions are tested with January / whole-year periods (e.g. 2025-01 vs 2026-01 for the benefit increase; 2026-01 vs 2027-01 for the post-2026 FPG standard), per PolicyEngine's YYYY / YYYY-01 test-period rule.
• make format passes; all expected values independently verified via direct simulation.

Verification note

Amounts are verified against primary sources. The current FSSA Chapter 3000 labels the maximum-benefit chart "effective 7/1/2025," while FSSA Transmittal 2024 and the SEA 265 amendment to IC 12-14-2-5 specify 7/1/2024. This PR models the currently-published FSSA chart date (2025-07-01) and cites both. The gross-income screen follows the FSSA §3010.15.00 "less than" wording (strict <); IC 12-14-1-1.7 phrases the limit as "not more than" (≤), which differs only for income at the exact rounded threshold.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (28c8085) to head (c4c368e).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files            2         8    +6     
  Lines           46       116   +70     
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+ Hits            46       116   +70     

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unittests	100.00% <100.00%> (ø)

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