An agency may pay the premium pay on an annual basis referred to in § 550.141 to an employee who meets the requirements of that section, at one of the following percentages of that part of the employee's rate of basic pay which does not exceed the minimum rate of basic pay for GS-10 (including any applicable locality-based comparability payment under 5 U.S.C. 5304 or special rate of pay under 5 U.S.C. 5305 or similar provision of law):

A position with a tour of duty of the 24 hours on duty, 24 hours off duty type and with a schedule of: 60 hours a week—5 percent, unless 25 or more hours of actual work is customarily required, in which event—10 percent; 72 hours a week—15 percent, unless 24 or more hours of actual work is customarily required, in which event—20 percent; 84 hours or more a week—25 percent.

A position with a tour of duty requiring the employee to remain on duty during all daylight hours each day, or for 12 hours each day, or for 24 hours each day, with the employee living at his station during the period of his assignment to his tour, and with a schedule of: 5 days a week—5 percent, unless 25 or more hours of actual work is customarily required, in which event—10 percent; 6 days a week—15 percent, unless 30 or more hours of actual work is customarily required, in which event 20 percent; 7 days a week—25 percent.

A position in which the employee has a basic workweek requiring fulltime performance of actual work, and is required, in addition, to remain on standby duty: 14 to 18 hours a week on regular workdays, or extending into a nonworkday in continuation of a period of duty within the basic workweek—15 percent; 19 to 27 hours a week on regular workdays, or extending into a nonworkday in continuation of a period of duty within the basic workweek—20 percent; 28 or more hours a week on regular workdays, or extending into a nonworkday in continuation of a period of duty within the basic workweek—25 percent; 7 to 9 hours on one or more of his regular weekly nonworkdays—15 percent; 10 to 13 hours on one or more of his regular weekly nonworkdays—20 percent; 14 or more hours on one or more of his regular weekly nonworkdays—25 percent.

When an agency pays an employee one of the rates authorized by paragraph (a)(1), (2), or (3) of this section, the agency shall increase this rate by adding (i) 21/2 percent to the rate when the employee is required to perform Sunday work on an average of 20 to 40 Sundays over a year's period or (ii) 5 percent to the rate when the employee is required to perform Sunday work on an average of 41 or more Sundays over a year's period but the rate thus increased may not exceed 25 percent.

If an employee is eligible for premium pay on an annual basis under § 550.141, but none of the percentages in paragraph (a) of this section is applicable, or unusual conditions are present which seem to make the applicable rate unsuitable, the agency may propose a rate of premium pay on an annual basis for OPM approval. The proposal shall include full information bearing on the employee's tour of duty; the number of hours of actual work required; and how it is distributed over the tour of duty; the number of hours in a standby status required and the extent to which the employee's whereabouts and activities are restricted during standby periods; the extent to which the assignment is made more onerous by night, holiday, or Sunday duty or by hours of duty beyond 8 in a day or 40 in a week; and any other pertinent conditions.