Section 831.2502 - Allowable service(a) Service credit deposits are not allowed for training periods prior to actual enrollment.(b) Service credit deposits can only be made for satisfactory volunteer service.(c) Annuitants enrolling as VISTA volunteers are not deemed reemployed annuitants. Service as a volunteer or volunteer leader performed after retiring under a CSRS or FERS retirement is not creditable serviced for retirement purposes.(d) Retirement credit is not allowable for training period(s) prior to actual enrollment.