Grumman claims USPS owes them $$millions -misunderstanding over $412  million contract discount PR note: I will  update this article in a few hours. Law360, New York (May 07, 2012, 3:19 PM ET) — Northrop Grumman Corp. on Friday sued the federal government for allegedly breaching an $874 million U.S. Postal Service contract by improperly delaying […]