(a) Except when the head of an agency determines that the agency would be seriously handicapped in carrying out its functions or that costs would be substantially increased, he or she shall provide that—

(1) Assignments to tours of duty are scheduled in advance of the administrative workweek over periods of not less than 1 week;

(2) The basic 40-hour workweek is scheduled on 5 days, Monday through Friday when possible, and the 2 days outside the basic workweek are consecutive;

(3) The working hours in each day in the basic workweek are the same;

(4) The basic nonovertime workday may not exceed 8 hours;

(5) The occurrence of holidays may not affect the designation of the basic workweek; and

(6) Breaks in working hours of more than 1 hour may not be scheduled in a basic workday.

(b)(1) The head of an agency shall schedule the work of his or her employees to accomplish the mission of the agency. The head of an agency shall schedule an employee's regularly scheduled administrative workweek so that it corresponds with the employee's actual work requirements.

(2) When the head of an agency knows in advance of an administrative workweek that the specific days and/or hours of a day actually required of an employee in that administrative workweek will differ from those required in the current administrative workweek, he or she shall reschedule the employee's regularly scheduled administrative workweek to correspond with those specific days and hours. The head of the agency shall inform the employee of the change, and he or she shall record the change on the employee's time card or other agency document for recording work.

(3) If it is determined that the head of an agency should have scheduled a period of work as part of the employee's regularly scheduled administrative workweek and failed to do so in accordance with paragraphs (b) (1) and (2) of this section, the employee shall be entitled to the payment of premium pay for that period of work as regularly scheduled work under subpart A of part 550 of this chapter. In this regard, it must be determined that the head of the agency: (i) Had knowledge of the specific days and hours of the work requirement in advance of the administrative workweek, and (ii) had the opportunity to determine which employee had to be scheduled, or rescheduled, to meet the specific days and hours of that work requirement.