(a) An agency may require that an employee with an uncommon tour of duty accrue and use leave on the basis of that uncommon tour of duty. The leave accrual rates for such employees shall be directly proportional (based on the number of hours in the biweekly tour of duty and the accrual rate of the corresponding leave category) to the standard leave accrual rates for employees who accrue and use leave on the basis of an 80-hour biweekly tour of duty. One hour (or appropriate fraction thereof) of leave shall be charged for each hour (or appropriate fraction thereof) of absence from the uncommon tour of duty.
(b) When an employee is converted to a different tour of duty for leave purposes, his or her leave balances shall be converted to the proper number of hours based on the proportion of hours in the new tour of duty compared to the former tour of duty.
(c) An agency shall establish an uncommon tour of duty for each firefighter compensated under part 550, subpart M, of this chapter. The uncommon tour of duty shall correspond directly to the firefighter's regular tour of duty, as defined in § 550.1302 of this chapter, so that each firefighter accrues and uses leave on the basis of that tour.