31 C.F.R. § 29.322
If an employee separates for disability retirement after June 30, 1997, and, on the date of separation, the employee—
(b) Does not satisfy the age and service requirements for optional retirement, the Federal Benefit Payment begins when the disability retiree reaches deferred retirement age. (See § 29.343.)
All Requirements for Credit Must Be Satisfied by June 30, 1997