(a) Coverage. (1) To obtain retirement benefits for a term of employment with the agency, an officer covered by subchapter III of chapter 83 of title 5 United States Code, within 90 days after the date he is separated from the agency, shall pay to OPM all necessary employee deductions and agency contributions for coverage under that subchapter for his term of employment with the agency. Interest shall not be charged an officer on any payment of necessary employee deductions and agency contributions. The amount of the employee deductions so paid shall be added to the officer's lump-sum credit in the Civil Service Retirement and Disability Fund.

(2) To retain coverage under chapter 87 of title 5, United States Code, during his term of employment with the agency, an officer covered by that chapter shall currently pay employee deductions and agency contributions necessary for coverage under that chapter for his term of employment with the agency. Collections may be made under procedures which may be determined in accordance with written agreements reached between accounting representatives of OPM and the agency.

(3) All retirement and insurance benefits and obligations shall be computed in the same manner as if the rate of basic pay the officer was receiving on the last day he was in his Federal position before employment with the agency had continued without change.

(4) An officer not covered by either subchapter III of chapter 83, or chapter 87, of title 5, United States Code, in the Federal position which he last held or from which he separates to enter employment with the agency does not acquire coverage or benefits under these statutes based on employment with the agency.

(b) Death coverage. An officer who dies during his term of employment or within 90 days of his separation therefrom is deemed to have died in the Federal Service.