Struggling homeowners who have complained for more than a year that the federal government’s loan modification program was unfair got some validation Thursday.

A new report from the Government Accountability Office (GAO) paints a picture of the Home Affordable Modification Program as an inconsistent effort with wide-ranging degrees of participation that could lead to different outcomes, even for borrowers who face similar personal circumstances.

Among the findings, the GAO found that among the 10 servicers it studied, which account for more than 70 percent of HAMP activity, there were seven different formulas for determining when a borrower was in imminent danger of default. Some servicers contacted borrowers who were 31 days delinquent while others contacted them 60 days or more after payments were missed or did not contact borrowers at all. As of this month, Treasury has instructed servicers to pre-screen all borrowers who have missed two mortgage payments for HAMP.

The report from Congress’ investigative arm also noted that the Treasury Department has not detailed any consequences for those servicers who do not follow the program. It said the latest component to the program, principal forgiveness, was totally voluntary.

“To date, more than 1.2 million homeowners took advantage of a trial modification receiving immediate payment relief averaging more than $500 per month and the number of permanent modifications is growing every month,” the Treasury Department said in a statement. “In total, HAMP modifications have already reduced mortgage payments for American homeowners by more than $2.2 billion.”