Opponents of the proposed tax limitation initiatives claimed Wednesday that a $100 million mistake was made when the initiatives were drafted.

Taxpayers For Utah said the initiatives will cut $180 million in property taxes instead of just the $80 million intended by its authors. The group began a radio ad campaign to publicize the claim and even bought time for it on K-Talk Radio - the unofficial home of the tax-reform movement.Pro-initiative leader Greg Beesley said his opponents' claims are wrong. "There was no mistake. $80 million is the correct figure and we will stand by it."

But former Gov. Scott M. Matheson, co-chairman of Taxpayer For Utah, said such agencies as the State Tax Commission and researchers for the Legislature agree with his group.

He said the mistake came because the state taxes only 80 percent of the fair market value of residential property, not 100 percent as he feels initiative supporters had assumed when they tried to cap taxes at .75 percent of their value.

The difference between figuring the value at 80 percent and 100 percent of fair market value is $100 million, Matheson said.

If opponents of the initiative are correct that wording of initiatives would still require assessing property at 80 percent of its value, the Legislature might be able to fix the problem and clarify the law. Matheson would not say whether his group would support such legislation if the initiatives pass.

Matheson attacked initiative supporters because of the claimed mistake, saying, "They really do not know what the real ramifications of their initiatives would be."

But Beesley fired back, saying his opponents and the state government should not cast stones because they have made mistakes of more than $100 million when estimating state tax surpluses in recent years.

Beesley also contends that the actual tax loss may be less than $80 million because the extra money returned to the private sector would increase property values and economic activity. He said when a similar initiative was passed in Massachusetts, the tax cut was only 60 percent of what the government estimated it to be.

Meanwhile, the heated debate on the expected impact of the initiatives continued.

University of Utah President Dr. Chase N. Peterson said Wednesday that if the tax initiatives on the November ballot pass, the U. will continue to function, but it will have lost quality - an elusive quantity that is hard to calculate.

That quality has been built into the U. over its history and sets it apart as a leader among Western states, where other state institutions haven't attained a comparable degree of quality, he said.

Speaking to members of advisory boards and others that are related to the university, Peterson outlined possible effects of reductions that would be required if the initiatives pass. They include enrollment caps, significant tuition increases and loss of faculty.

The related decline in quality would not be apparent, and the fact that the U. continued to operate might give tax protesters the impression that there was, in fact, excessive fat in the university's operations, Peterson said.

Higher education in Utah, in fact, could have to cut deeper into institution budgets than the predicted 13 percent if legislators decide public education will get a larger share of reduced tax revenues, he said.

Peterson said he believes the initiatives can be defeated, "not by the big guys, but at the grassroots if people learn it's in their self-interest to vote against them."