; and (B) is serving as such a law enforcement officer on such date. (3) Treatment of service performed by incumbents (A) In general Service described in paragraph (1) which is performed by an incumbent on or after the date of the enactment of this Act shall, for all purposes (other than those to which subparagraph (B) pertains), be treated as service performed as a law enforcement officer (within the meaning of section 8331(20) or 8401(17) of title 5, United States Code, as appropriate), irrespective of how such service is treated under subparagraph (B). (B) Retirement Service described in paragraph (1) which is performed by an incumbent before, on, or after the date of the enactment of this Act shall, for purposes of subchapter III of chapter 83 and chapter 84 of title 5, United States Code, be treated as service performed as a law enforcement officer (within the meaning of such section 8331(20) or 8401(17), as appropriate), but only if an appropriate written election is submitted to the Office of Personnel Management within 5 years after the date of the enactment of this Act or before separation from Government service, whichever is earlier. (4) Individual contributions for prior service (A) In general An individual who makes an election under paragraph (3)(B) may, with respect to prior service performed by such individual, contribute to the Civil Service Retirement and Disability Fund the difference between the individual contributions that were actually made for such service and the individual contributions that should have been made for such service if the amendments made by subsection (a) had then been in effect. (B) Effect of not contributing If no part of or less than the full amount required under subparagraph (A) is paid, all prior service of the incumbent shall remain fully creditable as law enforcement officer service, but the resulting annuity shall be reduced in a manner similar to that described in section 8334(d)(2) of title 5, United States Code, to the extent necessary to make up the amount