Update NY Essential Plan expansion after 2026 waiver termination

[daphnehanse11]

Background

PR #8127 added Basic Health Program modeling and correctly routes New York Essential Plan enrollees away from ACA premium tax credit eligibility.

However, New York's 200%-250% FPL Essential Plan expansion is no longer an indefinite policy path. CMS approved New York's request to terminate the Section 1332 waiver effective 2026-07-01. After that date, the Essential Plan returns to the core Basic Health Program population below 200% FPL, while the 200%-250% FPL expansion group transitions back toward Qualified Health Plans / ACA PTC if otherwise eligible.

Sources:

• PR Model Basic Health Program as separate coverage (fixes #8112) #8127: Model Basic Health Program as separate coverage (fixes #8112) #8127
• NY DOH 2026 waiver termination update: https://www.health.ny.gov/press/releases/2026/2026-03-23_federal_approval_to_preserve_health_coverage.htm
• CMS Section 1332 waiver page: https://www.cms.gov/marketplace/states/section-1332-state-innovation-waivers

Current model concern

In #8127, expanded_income_limit_states.yaml adds NY from 2025 onward and the changelog says eligibility enforces the statutory 133%-200% FPL band, with 250% FPL in NY from 2025.

That looks right for annual 2025 modeling, but it appears to carry the 250% FPL ceiling forward indefinitely. As of the 2026 waiver termination, NY should revert to the standard 200% FPL BHP ceiling after 2026-07-01.

Suggested fix

• Add a dated rollback for NY in gov/hhs/basic_health_program/eligibility/expanded_income_limit_states.yaml.
• Since is_basic_health_program_eligible is YEAR-defined, decide how to handle 2026:
  • minimally, make 2027+ use the standard 200% FPL ceiling; and
  • either document the annual 2026 convention or move the relevant BHP / ACA interaction to monthly or prorated logic.
• Add a regression test that a NY adult at 225% FPL is not BHP-eligible in 2027 and can flow to ACA PTC if otherwise eligible under federal rules.
• Add/adjust a 2026 test once the annual-vs-monthly treatment is chosen.

Example test cases

• NY adult at 225% FPL in 2025: BHP eligible, ACA PTC ineligible.
• NY adult at 225% FPL in 2027: BHP ineligible; ACA PTC eligibility depends on federal PTC rules and other coverage.
• NY adult at 190% FPL in 2027: still BHP eligible.