Washington — Those attending Tuesday’s meeting of an Education Department advisory committee on student-loan regulations witnessed an unusual event: Student-aid advocates agreed with the department over a proposal to eliminate a student-aid benefit.

But Wednesday’s meeting of the committee produced an equally unusual situation: Student-aid advocates on the committee sided with its loan-company representatives over the size of federal-subsidy payments to the lenders.

The panel is writing regulations for carrying out a law, enacted by Congress last September, that will cut $20-billion from the federal subsidy to private lenders participating in the government’s guaranteed-loan program. Most of the savings will go to the Pell Grant program.

Among other provisions, the law establishes a new income-based repayment plan that will give low-income college graduates greater flexibility in paying back their federally guaranteed student loans.

But representatives of loan companies such as Sallie Mae and Wachovia argued that the regulations proposed by the Education Department would not fully cover the federal government’s obligation to pay the subsidy costs in cases where the borrower is granted an extended income-based repayment schedule.

Larry Zaglaniczny, director of congressional relations for the National Association of Student Financial Aid Administrators, said the shortfall in federal-subsidy payments could be so great in some instances that lenders might have a clear economic incentive to steer borrowers toward a forbearance, in which the borrower makes no payments at all. In that case, the lender would get the full interest-subsidy payment from the government, while the borrower’s total overall debt would continue to grow.

Student-aid advocates participating in the panel’s discussions said the lenders appeared to have a point. The lenders wouldn’t be treated fairly by the department’s proposal, and students wouldn’t be served if their lenders had such a strong interest in promoting forbearance over an income-based repayment plan, said Robert M. Shireman, head of the Project on Student Debt, an advocacy group.

An Education Department lawyer, Brian P. Siegel, told the advisory panel that the department would consider the arguments. But then he warned: “The likelihood we’re going to change it is slim.”

Student-aid advocates, including Mr. Shireman, sided on Tuesday with the department over dropping an existing “hardship” provision that would have reduced interest payments for low-income college graduates by more than $1-billion over the next decade.

The hardship provision would have provided the same kind of benefit available through the new income-based repayment plan, but the hardship option has been especially helpful to doctors. They often have low incomes immediately following graduation but before they begin to earn salaries that make the hardship provision unnecessarily generous, Mr. Shireman said.

The advisory panel had been expected to finish its work on Thursday, at the end of its third three-day meeting in three months. But with some disputes remaining, the panel made plans to hold another session, on April 14-15. —Paul Basken