With nearly one in six student loan borrowers in default, the federal government is making changes to its income-based repayment plan to help borrowers with relatively high debt and low incomes keep up with their payments.

But a report that will be released on Tuesday by the New America Foundation, a nonprofit and nonpartisan policy institute, says the changes ultimately will provide only marginal help for low-income borrowers who are at the greatest risk of default.

Rather, the changes would provide big benefits to middle- and high-income borrowers, particularly for those seeking a graduate degree, the authors found. The report says that at least one financial planning company is telling law school students that the changes could allow them to write off $100,000 in student debt.

“If left unchanged, the program is set to provide huge financial windfalls to people who, far from being in need, are among the most financially well-off graduates in today’s job market,” the report says.