GAO made the recommendation after it analyzed FMS-related acquisition data between fiscal 2007 and fiscal 2016 as well as examined 32 FMS cases, the agency said in a report published Monday.
The report showed that firm-fixed-price contracts made up 99 percent of contract awards over the past decade and noted a rise in the use of fixed-price-incentive contracts by service branches for certain cases where cost savings could be achieved.
The congressional watchdog also identified factors that appear to contribute to price hikes and delays in FMS programs.
These include the discovery of defects in equipment during the testing phase, budget uncertainty and delays in contract awards.