Fairfax County supervisors yesterday questioned details and the proposed savings behind a plan by school officials to consolidate administrators in an office complex near Falls Church.

Board members said they want more information on the proposed $160 million deal before they consider approving it.

"We're being presented with half the equation," said Supervisor T. Dana Kauffman (D-Lee).

Squabbles between supervisors and school officials are nothing new to Fairfax and often involve budget issues. But yesterday's dust-up represents the first sign of tension between the board and the county's new school superintendent, Jack D. Dale, who is pushing the project.

The board also approved six initiatives to increase the supply of affordable housing through low-interest loans, rental apartments and construction of assisted living apartments for the elderly. As real estate prices have soared in Fairfax, the board has pushed for more housing for moderate- and low-income residents, particularly the elderly, making good on a pledge by Chairman Gerald E. Connolly (D) when he took office in January.

The School Board is scheduled to vote on the merger of school offices tonight. As many as 1,400 administrative staff members now scattered across 13 buildings would work instead in two side-by-side buildings: an existing one in Merrifield that the school system is negotiating to buy for an estimated $39.8 million and another one that would be built on land next door. The land would cost $6 million and the second building about $43.9 million.

Yesterday, several supervisors questioned the contention by school officials that the complex would save the district $5 million over 30 years from staff reductions and mileage reimbursements to employees who now shuttle between offices. They also expressed concern that the project, whose debt would be paid from the county treasury, would exceed Fairfax's limit on borrowing. School officials need to demonstrate how the project would free up money for desperately needed classrooms, they said.

"Do we accept the analysis of the school system that this will free up savings?" Connolly asked. "There may be other aspects of this we want an analysis of." Connolly said he is doubtful that the board would know enough to approve the project in December.

Dean Tistadt, assistant superintendent for facilities, said that if approval is delayed, the deal could be jeopardized.

Tistadt said he has been assured by county budget experts that paying for the project would not exceed the county's debt limit. He also said that the school system hopes to break even on the project, not necessarily save money. "If we can document this as a break-even transaction and increase our efficiencies, it makes a lot of sense to do it," he said.

The existing school-owned buildings would be sold or renovated for classrooms, Tistadt said.

The affordable housing projects would expand on existing programs and launch new ones. They include an application to the state for an $8 million loan fund to provide low-interest mortgages for homes valued at $360,000 or less; an application for another state grant that helps first-time buyers with down payments and closing costs; and a donation to an assisted living facility being renovated in Manassas for low-income seniors. About 60 percent of the residents are from Fairfax, said county housing official Mary Stevens.

The board also approved construction of a 60-unit assisted living facility and adult day-care program for low- and moderate-income seniors at Little River Glen, an independent living complex in Annandale. A private developer will build the apartments, and the county will lease them.

Also yesterday, Supervisor Penelope A. Gross (D-Mason) announced plans to rebuild the Mason District amphitheater, a popular cultural spot gutted last month by fire.