((a)) The Board shall determine the amount that is the present value (as of ) of future benefits payable from the Fund that are attributable to service in the participating uniformed services performed before . That amount is the original unfunded liability of the Fund. The Board shall determine the period of time over which the original unfunded liability should be liquidated and shall determine an amortization schedule for the liquidation of such liability over that period. Contributions to the Fund for the liquidation of the original unfunded liability in accordance with such schedule shall be made as provided in .

((b)) The Secretary of Defense shall determine, before the beginning of each fiscal year after , the total amount of the Department of Defense contribution to be made to the Fund for that fiscal year for purposes of section 1116(b)(2). That amount shall be the sum of the following:

((1)) The product of—

((A)) the current estimate of the value of the single level dollar amount to be determined under subsection (c)(1)(A) at the time of the next actuarial valuation under subsection (c); and

((B)) the expected average force strength during that fiscal year for members of the uniformed services under the jurisdiction of the Secretary of Defense on active duty and full-time National Guard duty, but excluding any member who would be excluded for active-duty end strength purposes by .

((2)) The product of—

((A)) the current estimate of the value of the single level dollar amount to be determined under subsection (c)(1)(B) at the time of the next actuarial valuation under subsection (c); and

((B)) the expected average force strength during that fiscal year for members of the Selected Reserve of the uniformed services under the jurisdiction of the Secretary of Defense who are not otherwise described in paragraph (1)(B).

((c))

((1)) Not less often than every four years, the Secretary of Defense shall carry out an actuarial valuation of the Fund. Each such actuarial valuation shall include—

((A)) a determination (using the aggregate entry-age normal cost method) of a single level dollar amount for members of the participating uniformed services on active duty and full-time National Guard duty, but excluding any member who would be excluded for active-duty end strength purposes by ; and

((B)) a determination (using the aggregate entry-age normal cost method) of a single level dollar amount for members of the Selected Reserve of the participating uniformed services who are not otherwise described by subparagraph (A).

((2)) If at the time of any such valuation there has been a change in benefits under the uniformed services retiree health care programs for medicare-eligible beneficiaries that has been made since the last such valuation and such change in benefits increases or decreases the present value of amounts payable from the Fund, the Secretary of Defense shall determine an amortization methodology and schedule for the amortization of the cumulative unfunded liability (or actuarial gain to the Fund) created by such change and any previous such changes so that the present value of the sum of the amortization payments (or reductions in payments that would otherwise be made) equals the cumulative increase (or decrease) in the present value of such amounts.

((3)) If at the time of any such valuation the Secretary of Defense determines that, based upon changes in actuarial assumptions since the last valuation, there has been an actuarial gain or loss to the Fund, the Secretary shall determine an amortization methodology and schedule for the amortization of the cumulative gain or loss to the Fund created by such change in assumptions and any previous such changes in assumptions through an increase or decrease in the payments that would otherwise be made to the Fund.

((4)) If at the time of any such valuation the Secretary of Defense determines that, based upon the Fund’s actuarial experience (other than resulting from changes in benefits or actuarial assumptions) since the last valuation, there has been an actuarial gain or loss to the Fund, the Secretary shall determine an amortization methodology and schedule for the amortization of the cumulative gain or loss to the Fund created by such actuarial experience and any previous actuarial experience through an increase or decrease in the payments that would otherwise be made to the Fund.

((5)) Contributions to the Fund in accordance with amortization schedules under paragraphs (2), (3), and (4) shall be made as provided in .

((d)) All determinations under this section shall be made using methods and assumptions approved by the Board of Actuaries (including assumptions of interest rates and medical inflation) and in accordance with generally accepted actuarial principles and practices.

((e)) The Secretary of Defense shall provide for the keeping of such records as are necessary for determining the actuarial status of the Fund.