10 percent for 25 percent . (2) Correction window For purposes of this subsection, the term correction window means the period of time beginning on the date on which the tax under subsection (a) is imposed with respect to a shortfall of distributions from an individual retirement plan, and ending on the earlier of— (A) the date on which the Secretary initiates an audit, or otherwise demands payment, with respect to the shortfall of distributions, or (B) the last day of the second taxable year that begins after the end of the taxable year in which the tax under subsection (a) is imposed. . (c) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2020. 303. Performance benchmarks for asset allocation funds (a) In general Not later than 6 months after the date of the enactment of this Act, the Secretary of Labor (or the Secretary’s delegate) shall modify the regulations under section 404 of the Employee Retirement Income Security Act of 1974 ( 29 U.S.C. 1104 ) to provide that, in the case of a designated investment alternative which contains a mix of asset classes, a plan administrator may, but is not required to, use a benchmark which is a blend of different broad-based securities market indices if— (1) the blend is reasonably representative of the asset class holdings of the designated investment alternative