The annuity recomputation required by paragraph (1) shall not apply to any participant who was entitled to an annuity under this subchapter on or before
September 8, 1982, or who is entitled to a deferred annuity based on separation from the Agency occurring on or before such date. Instead of an annuity recomputation, the annuity of such participant shall be reduced at age 62 by an amount equal to a fraction of the participant’s old-age or survivors’ insurance benefits under
section 402 of title 42. The reduction shall be determined by multiplying the participant’s monthly Social Security benefit by a fraction, the numerator of which is the participant’s total military wages and deemed additional wages (within the meaning of
section 429 of title 42) that were subject to Social Security deductions and the denominator of which is the total of all the participant’s wages, including military wages, and all self-employment income that were subject to Social Security deductions before the calendar year in which the determination month occurs.