Barely a week after the Legislature approved a budget that local and state officials said would slash state aid to Madison schools by no more than 10 percent, new estimates show the cuts will actually top 15 percent.

Word of the $9.2 million cut in general state school aids next year came as a rude shock to lawmakers and district officials. That’s because cuts approved by the Legislature’s budget committee were estimated to be 13.1 percent, but the final budget was believed to limit the cuts to 10 percent.

Dave Schmiedicke, Gov. Jim Doyle’s budget director, said several factors affected the new school funding calculation, including the number of students expected to enroll this fall, the district’s relatively larger increase in spending per student compared with other Wisconsin districts and the district’s high property values.

More than 100 other districts are facing state general aids cuts of about 15 percent, he said, but all of them are smaller than Madison. Overall, general school aids will be cut 3 percent next school year, Schmiedicke said.

Madison schools superintendent Dan Nerad said it was too early to say what the effect of the cuts would be on school programs or property taxpayers, who could pay more to make up for the reduction in state aid.

He and other district officials have contacted Doyle’s office and local lawmakers to see whether any changes in aid levels can be made.

Sen. Mark Miller, D-Monona, co-chairman of the Legislature’s budget committee, said the Legislature can always change the law. In general, however, the projected allocation for Madison is the result of the state’s complex school finance formula, which can’t be changed easily, he said.

The estimates released this week by the state Department of Public Instruction are preliminary and could change when final general school aid figures are set in October. The numbers do not include state spending on targeted programs such as special education or initiatives to reduce class sizes.

Under the estimates, Madison would get $51.5 million from the state next year in general aid, down from $60.7 million this year. The district’s proposed 2009-10 budget is $368 million.

But it wasn’t supposed to be like this.

Lawmakers last week added a change to the 2009-11 state budget that officials said was intended to limit cuts to any one district to 10 percent.

But that claim was based on calculations made with 2007-08 school enrollment and spending figures. The estimates for 2009-10 are based on enrollment and spending data from last school year and were not affected by the change, according to the Legislative Fiscal Bureau.

“The outcome is not what the Legislature or the administration expected, whether they admit it or not,” said Andrew Reschovsky, a UW-Madison economist and specialist in school funding.

Madison’s projected cut would have been even greater — about $27 million — were it not for a state law that limits cuts in the majority of general state aids to 15 percent, Schmiedicke said. Madison’s projected cut is actually slightly above that, at 15.2 percent, because funding for all districts is further reduced to pay for charter schools, he said.

State Journal reporter Patricia Simms contributed to this report.