subsection (a)(1)(A) shall be construed to prevent an employer from imposing a reasonable time period, based upon all the facts and circumstances, during which the employee must complete the reasonable alternative standard. Such a reasonable alternative standard (or waiver of the otherwise applicable standard) is provided for in section 2705(j)(3)(D) of the Public Health Service Act ( 42 U.S.C. 300 gg–4(j)(3)(D)) (and any regulations promulgated with respect to such section by the Secretary of Labor, the Secretary of Health and Human Services, or the Secretary of the Treasury).