The city’s affordable-housing formula was approved Monday after long debate that saw two members seek dramatic change based largely on frustration over how affordable housing is clustered in parts of the community, rather than spread evenly throughout.

Councillors Tim Toomey and Craig Kelley voted to send Community Preservation Act funding, with which communities get state matching funds on a local property tax surcharge, back to committee. There it was to be revised to put only 50 percent into affordable-housing expenditures, down from 80, while increasing historic preservation and open space expenditures to 25 percent each from 10 percent.

Their effort failed under opposition from every other councillor but Denise Simmons, who was out of the room during the vote, and the traditional 80/10/10 split was approved by the same ratio: six in favor, Toomey and Kelley opposed and Simmons temporarily absent.

City councillors Tim Toomey and Craig Kelley voted to change the city’s affordable housing formula Monday after noting inequalities in how recipients are clustered in the city.

Toomey and Kelley went on to vote against most in a long series of related expenditures read out by councillor Marjorie Davis, who led the CPA ordinance effort and offered an impassioned defense of the formula after nearly two hours of discussion.

“If we’re frustrated with where affordable-housing money goes, it’s important we don’t do it in a way that affects the most vulnerable people in the city,” Decker said, citing $22 million spent in Cambridge over the past nine years — the act was signed into law in 2000 — to provide affordable housing for 1,000 people. Statewide, $360 million has been disbursed.

Cut that money in half and families with homes would be halved too, she said, “and who among us wants to choose the 500 families who can’t stay in Cambridge?”

The state’s proportion of funding to Cambridge has dwindled over the years as a result of economic pressure and on more cities and towns joining the program, meaning the pie is being split more ways. Once matching 100 percent of funds, the state delivered 35 percent last year, which city officials called the lowest since passage of the act. This year’s rate will again be 35 percent, and Decker said this made it all the more important that the city keeps its own formula at 80 percent.

Communities must vote to take part in the act and decide the rate for its property tax surcharge. Cambridge’s is the highest possible, at 3 percent.

“It gets to the point where it’s really just a local levy,” councillor Sam Seidel said of the diminishing state aid.

For Toomey, the debate was a return to an issue from past months in which seven Jesuit properties near Harvard Square were snatched up by the Harvard Graduate School of Design. Those units could have been turned into affordable housing, Toomey said, but the city’s offer to buy was lackluster and came too late — revealing a lack of interest in having affordable housing in the city’s showcase areas, while neighborhoods such as East Cambridge got a disproportionate amount of it.

A solution with problems

While councillor Leland Cheung voted against Toomey’s proposed change in the formula, he acknowledged the problem.

“The point to CPA is to give everyone the chance to live in Cambridge, not so they can all live in East Cambridge,” Cheung said.

Kelley, who backed Toomey’s revision, said he disagreed with the current formula and felt there had been a lack of public discussion in setting it. “To the best of my knowledge there’s been no open discussion,” he said. “Until the money is taken off the table, I don’t think there will be. This is the only method of persuasion we seem to have.”

Several people spoke on the matter during the public comment period that opens council meetings. Among them were Elaine DeRosa, director of the Cambridge Economic Opportunities Committee, who noted that some of the need for affordable housing — and for the CPA formula to stay where it was — could be traced back to the end of rent control in Cambridge; and Urszula Masny-Latos, a Rindge Avenue resident whose story corroborated that view.

In 1998, she and 41 other residents of an apartment building — a crowd ranging from students and teachers to artists and lawyers — faced the loss of their homes when the landlady died and new owners announced rent would be doubled. “We tried to find new places to live,” Masny-Latos said. “It was difficult. We realized Cambridge was becoming a city just for the rich.”

Given two years to “put our lives together,” Masny-Latos said that through affordable housing she was able to find a home in Cambridge for herself and her son.

“I’m the only lucky person out of the whole group,” she told the council. “Everyone else was forced to move” to other cities.