550.122—Computation of night pay differential.
(a) Absence on holidays or in travel status.
An employee is entitled to a night pay differential for a period when he is excused from nightwork on a holiday or other nonworkday and for night hours of his tour of duty while he is in an official travel status, whether performing actual duty or not.
(b) Absence on leave.
An employee is entitled to a night pay differential for a period of paid leave only when the total amount of that leave in a pay period, including both night and day hours, is less than 8 hours.
(c) Relation to overtime, Sunday, and holiday pay.
Night pay differential is in addition to overtime, Sunday, or holiday pay payable under this subpart and it is not included in the rate of basic pay used to compute the overtime, Sunday, or holiday pay.
(d) Temporary assignment to a different daily tour of duty.
An employee is entitled to a night pay differential when he or she is temporarily assigned during the administrative workweek to a daily tour of duty that includes nightwork. This temporary change in a daily tour of duty within the employee's regularly scheduled administrative workweek is distinguished from a period of irregular or occasional overtime work in addition to the employee's regularly scheduled administrative workweek.