Applicable employer-sponsored coverage shall include coverage under any group health plan established and maintained primarily for its civilian employees by the Government of the United States, by the government of any State or political subdivision thereof, or by any agency or instrumentality of any such government. (5) Cost of coverage (A) Health FSAs In the case of applicable employer-sponsored coverage consisting of coverage under a flexible spending arrangement (as defined in section 106(c)(2)), the cost of the coverage shall be equal to the amount determined under rules similar to the rules of section 4980B(f)(4) with respect to any reimbursement under the arrangement reduced by the contributions described in subsection (a)(14)(B). (B) Archer MSAs and HSAs In the case of applicable employer-sponsored coverage consisting of coverage under an arrangement under which the employer makes contributions described in subsection (b) or (d) of section 106, the cost of the coverage shall be equal to the amount of employer contributions under the arrangement. (C) Allocation on a monthly basis If cost is determined on other than a monthly basis, the cost shall be allocated to months in a taxable period on such basis as the Secretary may prescribe. . (c) Clerical amendment The table of sections for chapter 43 of such Code is amended by striking the item relating to section 4980I. (d) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017.