Notwithstanding any other provision of this section (except paragraph (3) of this subsection) or section
2083 of this title, any military service (other than military service covered by military leave with pay from a civilian position) performed by a participant after December 1956 shall be excluded in determining the aggregate period of service on which an annuity payable under this subchapter to such participant or to the participant’s spouse, former spouse, previous spouse, or child is based, if such participant, spouse, former spouse, previous spouse, or child is entitled (or would upon proper application be entitled), at the time of such determination, to monthly old-age or survivors’ insurance benefits under section
402 of title
42, based on such participant’s wages and self-employment income. If the military service is not excluded under the preceding sentence, but upon attaining age 62, the participant or spouse, former spouse, or previous spouse becomes entitled (or would upon proper application be entitled) to such benefits, the aggregate period of service on which the annuity is based shall be redetermined, effective as of the first day of the month in which the participant or spouse, former spouse, or previous spouse attains age 62, so as to exclude such service.