(a) Payments shall be based on the rate of pay (including allowances, differentials, or other authorized payments) to which the employee was entitled immediately before the issuance of the order of evacuation. All deductions authorized by law, such as retirement or social security deductions, authorized allotments, Federal withholding taxes, and others, when applicable, shall be made before advance payments or evacuation payments are made.

(b)(1) The amount of advance payments shall cover a time period not to exceed 30 days or a lesser number of days, as determined by the authorizing agency official.

(2) Evacuation payments shall cover the period of time during which the order to evacuate remains in effect, unless terminated earlier, but shall not exceed 180 days. When feasible, evacuation payments shall be paid on the employee's regular pay days.

(c) When an advance payment has been made to or for the account of an employee, the amount of the advance payment shall not diminish the amount of the evacuation payments that would otherwise be due the employee.

(d)(1) For full-time and part-time employees, the amount of an advance payment or an evacuation payment shall be computed on the basis of the number of regularly scheduled workdays for the time period covered.

(2) For intermittent employees, the amount of an advance payment or evacuation payment shall be computed on the basis of the number of days on which the employee would be expected to work during the time period covered. The number of days shall be determined, whenever possible, by approximating the number of days per week normally worked by the employee during an average 6-week period, as determined by the agency.