(a) An election under §847.411 is effective on the first day of NAFI employment subject to retirement coverage following CSRS- or FERS-covered employment.

(b) Deductions and contributions for CSRS or FERS coverage under §831.111 or §841.501 of this chapter begin effective on the first day of the next pay period after the agency receives the employee's election under §847.411(a).

(c) An election under §847.411 is irrevocable when received by the employing agency.

(d) NAFI service performed on and after the effective date of an election under §847.411 becomes fully creditable for retirement eligibility and computation of the annuity benefit, including computation of average pay.