When operations in an official plant require the services of inspection personnel beyond their regularly assigned tour of duty on any day or on a day outside the established schedule, such services are considered as overtime work. The official plant must give reasonable advance notice to the inspector of any overtime service necessary and must pay for such overtime. For each calendar year, FSIS will calculate the overtime rate for inspection service, per hour per program employee, using the following formula: The quotient of dividing the Office of Field Operations plus Office of International Affairs inspection program personnel's previous fiscal year's regular direct pay by the previous fiscal year's regular hours, plus the quotient multiplied by the calendar year's percentage of cost of living increase, multiplied by 1.5, plus the benefits rate, plus the travel and operating rate, plus the overhead rate, plus the allowance for bad debt rate. FSIS calculates the benefits rate, the travel and operating rate, the overhead rate, and the allowance for bad debt rate using the formulas set forth in § 592.510(b) and the cost of living increases and percentage of inflation factors set forth in § 592.510(c) of this chapter.