A two-year study of Montgomery County's property tax assessment practices has concluded that numerious inequities exist, resulting in a "tendency" to favor higher priced homes and give businesses a tax break unavailable to residences.

Eliminating the inequities would not necessarily lower the average home owner's tax bill, but could satisfy widespread taxpayer complaints that the highly complex assessment system treats various properties and neighborhoods unequally, according to the head of the study.

Charles C. Joyce Jr., chairman of the Task Force of Real Property Assessment Practices, told the County Council yesterday that the "subjectivity" of the tax assessor's job contributes to the inequities listed in the report.

Supervisor of Assessments Robert L. Rudnick declined to comment on the 200-page report because he had not read it, but he did defend his staff as adhering to state assessment regulations.

"I have been here 14 years and I haven't seen enormous inequities," Rudnick said.

In Maryland, the property tax bill is made up of two components -- state assessments of property value at 45 percent of the fair market price and property tax rates applied to those assessments by local governments.

Analyzing data for the 1977 tax bills, in which assessments were supposed to be based on 50 percent of fair market value, the task force found these disparities:

While the average house in the county was assessed only at 41 percent of the fair market value, about 18 percent of the properties studied were assessed below 38 percent and 39 percent were assessed above 44 percent of their value.

Because of the apparent variance in assessment-sales ratios in different parts of the county, many properties in Bethesda, for example, were underassessed compared to properties in Gaithersburg.

Pointing to a "tendency" to favor higher-priced homes over lower-priced ones, the report showed that the average house valued up to $50,000 was assessed at 44 percent of its value, while the average house valued over $150,000 was assessed at only 37 percent of its value.

Had the assessments been applied uniformly, the owner of the $50,000 home would have paid $46.80 less and the owner of the $150,000 home would have paid $168 more, the calculations showed.

The task force laid part of the blame for this discrepency on the practice of computing assessments from 12 to 30 months before the property tax rate is applied to them. Even if assessments on all categories are calculated uniformly, higher-priced properties appreciate more rapidly than lower priced ones. The result is a discrepancy in the assessment-sale ratios that tends to favor the higherpriced homes by the time the tax is levied, the report contended.

"We don't see the basis for that time lag," said Joyce in criticizing the assessment system.

The report also found that assessment-sales ratios vary widely among different classes of property. The average condominium, for example, was assessed at 45 percent of its value while the average apartment was assessed at 37 percent.

It also showed that in the six years before 1977 assessments on existing commercial-industrial properties increased by 30 percent in contrast to the 102 percent rise in assessments on single-family homes.

In addition, the task force concluded that commercial-industrial property was "seriously underassessed" at 37 percent of its value.

Rudnick and others disputed that claim, saying the low frequency of commercial sales makes it difficult to compute a fair market value for commercial properties. The same rule applies to the difference between classes of property, such as singlefamily homes and apartment buildings, which appreciate at different rates, they said.

"I hope no one thinks this can be rectified right away," said new County Council President Neal Potter, the council's tax expert. "This is a great long-term agenda."