Section 531.412 - Effective date of a within-grade increase(a) Except as provided in paragraph (b) of this section, a within-grade increase shall be effective on the first day of the first pay period following completion of the required waiting period and in compliance with the conditions of eligibility. Interim within-grade increases shall become effective as provided in § 541.414(b) .(b) When an acceptable level of competence is achieved at some time after a negative determination, the effective date is the first day of the first pay period after the acceptable determination has been made.46 FR 2319, Jan. 9, 1981, as amended at 46 FR 41020, Aug. 14, 1981; 59 FR 24029, May 10, 1994