The Secretary of the Navy requested a decision as to what, if any, corroborative evidence must be required before payment based on corrections in change of duty orders properly may be made.GAO found that the circumstances in which an attempted retroactive modification or correction of a travel order may be recognized as authorizing an additional payment for prior travel are so exceptional that cla...

TRAVEL ORDERS - RETROACTIVE MODIFICATION TO CHANGE METHOD OF REIMBURSEMENT THE EXISTENCE AT THE TIME A NAVY OFFICER'S TRAVEL ORDERS AUTHORIZING MILEAGE WERE ISSUED OF AN ADMINISTRATIVE PRACTICE TO AUTHORIZE PER DIEM INSTEAD OF MILEAGE FOR THE CLASS OF TRAVEL AND TEMPORARY DUTY INVOLVED- - WHERE NOT MADE MANDATORY BY COMPETENT REGULATIONS. ALTHOUGH THE ORDERS MAY HAVE BEEN ISSUED IN DISREGARD OR IG...