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 unpaid. (C) Prior service defined For purposes of this subsection, the term prior service means, with respect to any individual who makes an election under paragraph (3)(B), service (described in paragraph (1)) performed by such individual before the date as of which appropriate retirement deductions begin to be made in accordance with such election. (5) Government contributions for prior service (A) In general If an incumbent makes an election under paragraph (3)(B), the agency in or under which that individual was serving at the time of any prior service (referred to in paragraph (4)) shall remit to the Office of Personnel Management, for deposit in the Treasury of the United States to the credit of the Civil Service Retirement and Disability Fund, the amount required under subparagraph (B) with respect to such service. (B) Amount required The amount an agency is required to remit is, with respect to any prior service, the total amount of additional Government contributions to the Civil Service Retirement and Disability Fund (above those actually paid) that would have been required if the amendments made by subsection (a) had then been in effect. (C) Contributions to be made ratably Government contributions under this paragraph on behalf of an incumbent shall be made by the agency ratably (on at least an annual basis) over the 10-year period beginning on the date referred to in paragraph (4)(C). (6) Exemption from mandatory separation Nothing in section 8335(b) or 8425(b) of title 5, United States Code, shall cause the involuntary separation of a law enforcement officer (as described in paragraph (1)) before the end of the 3-year period beginning on the date of the enactment of this Act. (7) Regulations The Office shall prescribe regulations to carry out this section,