[Request for Retroactive Modification of Rate Tender]

The General Services Administration (GSA) requested an advance decision on whether it properly disallowed a carrier's claims for additional charges for transportation services due to a retroactive modification of a tender in a Guaranteed Traffic program solicitation for the Military Traffic Management Command (MTMC). MTMC contended that an agency can waive a tender provision even though the waiver has the effect of increasing rates. GSA contended that the lower rates in the initial tender were applicable at the time of the movement and, in the absence of consideration of the waiver of that contractual right, there was no authority to agree with the retroactive modification of that tender. GAO held that: (1) where it has not been shown that the government received any benefit from a modification, and no officer or employee of the government can waive, modify, or otherwise change contractual obligations without a compensatory benefit, the modification is not retroactively effective; (2) the carrier has the burden of showing that any special services it billed were requested and performed; and (3) Guaranteed Traffic agreements may preclude the use of lower rates published in existing tenders, but new agreements must provide that lower rates in other tenders will not be applicable. GAO found that: (1) the modified tender did not supersede, but specifically permitted the use of other tenders offering lower rates; and (2) there was nothing in the record to show that special services offered at no extra charge were requested or performed on the shipments involved. Accordingly, GSA properly disallowed the carrier's claim.