Claim for Additional Per Diem and Mileage Incident to Temporary Duty

A civilian employee claimed additional per diem allowances and mileage expenses incident to a temporary duty assigment to attend a training course. Although the employee's travel orders authorized only $12 per diem, Joint Travel Regulations provide for a maximum rate of $25. The employee may be reimbursed for the difference in per diem rates, but he is not entitled to mileage expenses since the agency did not authorize such expenses.