5 CFR 846.401 - Refunds of excess contributions.
(a) An individual who elects FERS coverage is entitled to a refund of CSRS contributions made prior to the effective date of the election for service that is subject to FERS computation under § 846.304(c) (if not already refunded) which exceed the contributions required under FERS, as provided by this section.
(b) The refund is equal to -
(c) A refund made under this section is payable with interest computed as prescribed under § 831.105 (d) and (e) of this chapter. Interest is payable regardless of the length of the period of service for which refund is being made or the total amount of service the employee has.