It’s a double whammy for taxpayers in Ann Arbor and beyond.

And it’s resulted in a record number of property tax appeals to the state in the last couple years.

As frustrated taxpayers watch their property values plummet, they get assessment notices that show their taxable values - the basis for determining their property taxes - increasing.

This year is shaping up to be another busy year for the Michigan Tax Tribunal.

Friday was the deadline for appeals, which could increase by 70 percent from a year ago to about 28,500, said Peter Kopke, chief clerk of the Tax Tribunal.

That compares to typical totals of about 8,000 filings per year before the housing market decline, Kopke said.

As of last week, Washtenaw County property owners had filed 78 new cases, Kopke said. He said he was unsure how that compared to the previous year.

Eric Joffe, 31, of Ann Arbor, is among those who have appealed to the state.

"Since last year, the market's gotten worse and to say, 'Oh, your home went up in value or it stayed the same,' that's just not true," said Joffe, who lives on Hilltop Drive off Jackson Avenue.

The city has Joffe's assessed value and taxable value both set at $87,500, meaning his home is theoretically worth about $175,000. That's the same as in 2008, city records show.

But Joffe said the numbers should be less. Houses in the neighborhood where he and his wife Tisha live have sold recently for $111,000 and $140,000, he said.

City Assessor David Petrak declined to comment about the Joffes' case, but said the State Tax Commission requires governments to use a one- or two-year sales study when determining taxable value. In times of a declining market, the city uses a one-year study.

For 2009 assessments, Ann Arbor studied sales from October 2007 to September 2008.

“What we did see was a fair number of people who came into the (city) Board of Review and said ‘Here’s what other homes sold for in my neighborhood.’ And we said, ‘When did they sell?’ And they said, 'February and January.’ In a declining market, those potentially would have sold for less than a year ago," Petrak said.

The deadline has already passed for cases that go before the Full Tribunal, which handles more complicated cases that typically involve industries and corporations represented by attorneys.

“I would say we probably had twice as many claims this year as last year,” Petrak said, referring to the number of Full Tribunal filings.

Petrak didn’t have final figures, but he said he expects 70 new Full Tribunal cases filed this year, bringing the city’s total pending cases before the state to about 150.

Friday's deadline applied to small claims filings in the Tax Tribunal that typically involve appeals filed by homeowners who represent themselves.

Government officials say there's a good reason why your taxes can go up even as the value of your home goes down.

Proposal A, the 1994 voter-approved measure that sets the rules for Michigan property tax collection, limited taxable value increases to the rate of inflation even when property values were rising faster than that. At that time, assessed values that represent half the true cash value of a property increased at a greater rate, creating a gap between the two figures.

But when assessed values go down, if the separation between that figure and the taxable value is great enough, the taxable value continues to rise.

Washtenaw County Treasurer Catherine McClary said it’s too soon to tell whether the number of tribunal appeals in the county will increase again this year.

“The big year was 2008,” she said.

The treasurer’s office processes billings or refunds to taxpayers once a case is decided in the Tribunal - whether it be through an agreement between the two parties, a dismissal or a decision by the Tribunal.

Last year, McClary said her office processed 225 cases involving 130 parcels and 175 years of disputed taxes. That compares to 92 in 2007 and 71 in 2006.

Decisions and consent agreements can have a large financial impact on local and state governments, particularly when they involve big taxpayers.

They can force governments to reimburse the taxpayer for money already collected. In the Pfizer case, that adds up to nearly $10 million the local and state government must pony up as the result of an agreement with Pfizer that was reached after the company appealed its 2008 and 2009 taxes.

The dispute involved Pfizer’s closed research center campus at Plymouth Road and Huron Parkway.

The agreement affects the city of Ann Arbor, Ann Arbor Public Schools, Washtenaw County, the Ann Arbor Public Library, the Washtenaw Intermediate School District Washtenaw Community College and the state of Michigan education tax.

It dropped Pfizer’s 2008 tax bill from $12.5 million to $7 million and its 2009 taxes from $10.9 million to $6.4 million.

That’s costing the city of Ann Arbor nearly $2 million.

Kopke said it can take a year or more for the Tax Tribunal to hear more complicated cases that sometimes involve requests by the parties involved for more time. Some small claims cases filed last year were heard by December, he said.

Kopke didn't have recent data on the percentage of cases decided for the property owner or the government, but said property owners prevailed about half the time when numbers were studied in the 1990s.

The Web site UPI.com reported last month that more U.S. homeowners are appealing increased property taxes or seeking reassessments amid the drop in home values, with officials across the country saying the number of appeals is rising dramatically.

Photo by Lon Horwedel, AnnArbor.com: Eric and Tisha Joffe aren't pleased at their recent tax assessment and are appealing to the state.