The report by the Government Accountability Office also noted the challenges of making postal cuts due to community opposition. Hundreds of postal employees in cities around the nation in recent weeks have rallied to draw attention to the proposed cuts and urge lawmakers to oppose them.
Donahoe has said communities on the final closure list will be notified in July.
"The Postal Service is at a crossroads. Our business model is broken," Donahoe recently told a House hearing. He has previously criticized the Senate measure as offering only a short-term revenue fix. "We have insufficient revenue to cover our costs ... If the Postal Service were a private company, we would be engaged in Chapter 11 bankruptcy proceedings."
The Postal Service, an independent agency of government, is subject to congressional control on major aspects of its operations.
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.