; and (2) in subsection (f)(2)(B)(i), by striking 400 each place such reference appears and inserting 600 in each such place. (c) Effective date The amendment made by this section shall apply to taxable years beginning after December 31, 2021. 227. Premium assistance Notwithstanding any other provision of law, the Secretary of the Treasury shall calculate the credit allowable under section 36B of the Internal Revenue Code of 1986 based on the taxpayer’s prior year tax return and the Secretary of Health and Human Services shall provide for open enrollment periods that end on April 15. 228. Adding copper plans to Exchanges (a) In general Section 1302 of the Patient Protection and Affordable Care Act ( 42 U.S.C. 18022 ) is amended— (1) in subsection (a)(3), by inserting copper, after either the ; (2) in subsection (c), by adding at the end the following new paragraph: (5) Special rule for copper plans A health plan in the copper level of coverage (as described in subsection (d)(1)(E)) shall be deemed to meet the requirements of this subsection. ; (3) in subsection (d)— (A) in paragraph (1), by adding at the end the following new subparagraph: (E) Copper level A plan in the copper level shall provide a level of coverage that is designed to provide benefits that are actuarially equivalent to 50 percent of the full actuarial value of the benefits provided under the plan and will have out-of-pocket limits that are 30 percent higher than bronze plans. ; and (B) in paragraph (4)— (i) by inserting copper, after any reference to a ; and (ii) by inserting copper, after providing a