(a)     Subject to any limitation prescribed by the Office of Personnel Management or the agency, a full-time employee on a flexible schedule can accumulate not more than 24 credit hours, and a part-time employee can accumulate not more than one-fourth of the hours in such employee's biweekly basic work requirement, for carryover from a biweekly pay period to a succeeding biweekly pay period for credit to the basic work requirement for such period.

  (b)     Any employee who is on a flexible schedule program under section 6122 of this title and who is no longer subject to such a program shall be paid at such employee's then current rate of basic pay for -

            (1)     in the case of a full-time employee, not more than 24 credit hours accumulated by such employee, or

            (2)     in the case of a part-time employee, the number of credit hours (not in excess of one-fourth of the hours in such employee's biweekly basic work requirement) accumulated by such employee.