5 U.S.C. § 10205

(a) Definition .— In this section, the term “calendar week of active service” includes all periods of leave with pay or other paid time off, and periods of non-pay status which do not cumulatively equal one 40-hour workweek. (b) Adjustments .— Each member whose current performance is at an acceptable level of competence shall have a service step adjustment as follows: (1) Each member in service step 1, 2, or 3 shall be advanced successively to the next higher service step at the beginning of the first pay period immediately following the completion of 52 calendar weeks of active service in the member’s service step. (2) Each member in service step 4, 5, 6, 7, 8, 9, 10, or 11 shall be advanced successively to the next higher service step at the beginning of the first pay period immediately following the completion of 104 calendar weeks of active service in the member’s service step. (3) Each member in service step 12 shall be advanced successively to the next higher service step at the beginning of the first pay period immediately following the completion of 156 calendar weeks of active service in the member’s service step.