5 CFR 550.172: Relation to overtime, night, and holiday pay.

(a) Premium pay for Sunday work is in addition to premium pay for holiday work, overtime pay, or night pay differential payable under this subpart and is not included in the rate of basic pay used to compute the pay for holiday work, overtime pay, or night pay differential.

(b) For a Border Patrol agent covered by 5 U.S.C. 5550 and subpart P of this part, no Sunday premium pay is payable for regularly scheduled overtime hours within the agent's regular tour of duty, as required by 5 U.S.C. 5550(b)(2)(C), (b)(3)(C), and (c)(1)(A). The overtime supplement payable for such scheduled overtime hours is not part of the agent's rate of basic pay used in computing the Sunday premium pay for other hours that qualify for such premium pay.