The American aerospace and defense corporation Boeing overcharged the United States Army by 131.5 percent, according to an unredacted Department of Defense Office of Inspector General audit released by Project on Government Oversight (POGO).

According to the 142-page document, the Army should have only paid $10 million instead of the nearly $23 million it paid for spare parts for Boeing AH-64 Apache and Boeing CH-47 Chinook helicopters.

"The audit report raises significant questions about what the DoD is paying to maintain and operate major weapons," POGO explained. "For instance, the estimated 'sustainment' price tag for the Lockheed F-35 Joint Strike Fighter is $1 trillion over the next 50 years. The cost of spare parts makes up a portion of that $1 trillion figure. Spare parts overcharges become quite significant when you add up individual overcharges over time, over a number of weapon systems."

Boeing has only refunded approximately $1.3 million of the nearly $13 million that the audit calls for and the Army has been hesitant to seek further refunds.

The Army awarded Boeing with a contract to provide support for the helicopters in June 2004, instead of obtaining the parts through the Pentagon's Defense Logistics Agency. Bloomberg reported the Boeing contract intended to reduce the overhaul time for helicopters returning to combat by as much as 50 percent.