After collecting 1,498 pages of testimony from 134 witnesses during nine days of public hearings in February, March and April, the D.C. Zoning Commission decided last night that it needs more information to decide whether housing as well as commercial development should be required in areas of downtown still ripe for new construction.

The commission decided to seek more comments from the public and to hire a consultant independent of the D.C. government to help it understand the economic implications of the choices it faces, postponing any decision on downtown housing until September at the earliest.

The housing question, perhaps the most sweeping issue the commission has considered in 30 years, has divided planners and activists, who want to make downtown a place where people live as well as work, from builders, who say downtown housing is financially unrealistic.

Builders have argued that the city should allow them to develop office buildings downtown, which are more profitable, and then require them to subsidize housing for the poor in other parts of the city, where land is less valuable.

Commission members Lloyd Smith, the executive director of the Marshall Heights Community Development Corp., and Maybelle T. Bennett, research director for a lobbying group that addresses poverty issues, said the commission still does not know enough about the demand for downtown housing, its potential impact on D.C. tax revenue, and its potential effect on the economy as the real estate industry experiences a slowdown.

They said the commission's effort to encourage housing production would be self-defeating if it stifles development. "We may be creating requirements that can't be fulfilled realistically," Bennett said. "I don't think we can do it ourselves, and I think we're going to fall flat on our face if we try."

It was a change of heart for Smith, who had joined three other members of the commission last month in tentative support of a plan that would require developers of future downtown buildings to include housing in their projects but allow them to fulfill a quarter of their housing quota by funding affordable housing in other parts of the city. Bennett was absent from that meeting.

A coalition of planners, downtown activists and members of the Downtown Cluster of Congregations, a church group, have argued that downtown would be safer, livelier and economically stronger over the long-run if it had a larger residential population.

Builders said the plan the commission was considering could curtail development and damage the District's real estate tax base.

Zoning Commission Chairman Tersh Boasberg reluctantly agreed to postpone a decision, saying that the commission is unlikely to learn anything new. Boasberg, a lawyer and preservationist best known for his role in the campaign that blocked development of a shopping mall on the Manassas battlefield, had drafted the plan that fleetingly enjoyed the commission's support.

That plan departed sharply from the proposal originally submitted by Mayor Marion Barry's planning office. The planning office had proposed exempting many development sites and compensating developers for the housing requirement by allowing them to build larger buildings than the current zoning allows. Boasberg's plan eliminated the bonuses and exemptions.

The debate revealed deep differences among commission members. Bennett said downtown development should be used to generate funds for housing solely outside the downtown. But member John G. Parsons, who represents the National Park Service, said all of the housing should be developed within the downtown area.

Parsons said the commission should not be distracted by short-term economic considerations because it is deciding the shape of downtown for 50 to 100 years.

The plan tentatively endorsed by the commission last month provoked a backlash from nonprofit housing developers and a plea by the D.C. Downtown Partnership, an alliance of political, business and civic leaders, that the commission seek more information before voting.

Jim Dickerson, spokesman for a coalition of nonprofit housing developers, said the plan the commission was considering "smacks of elitism and racism" because it generally would produce luxurious condominiums for "wealthy people, white people," instead of affordable housing for "all the poor black people that have not a place to stay."

Harps & Harps Inc., a D.C. real estate appraiser, and Wilkes, Artis Hedrick & Lane, a law firm that represents developers, estimated that the plan the commission had tentatively endorsed would reduce the value of downtown land by $200 million.