((a)) Subject to subsections (b) and (c) of this section, the Secretary may from time to time adjust the dollar amount of the monthly installments payable to a beneficiary of United States Government Life Insurance who is receiving the proceeds of such insurance under a life annuity settlement option. The Secretary may make such an adjustment only if the Secretary determines that the adjustment is administratively and actuarially sound. The Secretary may make such an adjustment without regard to the provisions of with respect to interest rates and the use of mortality tables.
((b)) The Secretary shall determine the amount in the trust fund in the Treasury held for payment of proceeds to United States Government Life Insurance beneficiaries attributable to interest and mortality gains on the reserves held for annuity accounts. Such amount shall be available for distribution to the life annuitants referred to in subsection (a) of this section as a fixed percentage of, and in addition to, the monthly installment amount to which the annuitants are entitled under this subchapter. For the purposes of this section, gains on the reserves are defined as funds attributable solely to annuity accounts that are in excess of actuarial liabilities.
((c)) The monthly amount of an annuity authorized in , as adjusted under this section, may not be less than the monthly amount of such annuity that would otherwise be applicable without regard to this section.