Claiming that the contract between the West Tisbury assessors and Vision Appraisal Technology does not comply with state law, a town taxpayer called on the town selectmen this week to declare the 2007 real estate valuations invalid.

Joan Ames, a resident of Seven Gates Farm, told selectmen at their meeting Wednesday that Vision Appraisal, the Northboro company the town contracts with to prepare and update town property valuations, supplied the town with language for its request for proposals (RFP). This is in direct violation of the requirements set out by the state inspector general, Ms. Ames said.

Quoting from the state Uniform Procurement Act, Ms. Ames said procurement laws prohibit use of a single vendor’s specifications when drafting RFP language.

“It has come to [our] attention that Vision Appraisal has been supplying the selectmen’s office with their own RFP. We do not yet know how many years this practice has been used, but it is in direct violation of commonwealth laws as set forth by the inspector general,” Ms. Ames said.

Property taxes are the subject of growing discussion in West Tisbury; tax bills doubled and tripled in some neighborhoods this year — principally at Seven Gates Farm and around the Tisbury Great Pond — while in other neighborhoods they remained flat or actually went down. Last week the town assessors hosted a public session with a spokesman for Vision Appraisal to explain the process of developing valuations. A large group of taxpayers attended.

More than 100 abatement applications have been filed this year.

The town also remains locked in court with William W. Graham, the owner of a large property at Lambert’s Cove who is challenging his property assessments from earlier years. The subject of the longest running trial in the history of the Massachusetts Appellate Tax Board last year, the Graham case is now pending before the Massachusetts Court of Appeals.

On Wednesday Ms. Ames said an adjustment in the RFP language approved by the board of assessors this week still fails to meet state law requirements, and “once again blatantly favors Vision Appraisal, this time in the assessors’ own words,” she said.

Town executive secretary Jennifer Rand, who is also the procurement officer, responded that she, not the assessors, prepared the changed RFP language.

Selectman Jeffrey (Skipper) Manter 3rd told Ms. Ames that town counsel has consistently reviewed RFP contract language for compliance with state law. “But we’ll have counsel look at this,” he said.

In other business this week, selectmen and finance committee members wrestled without consensus around a format for a public finance forum planned to provide taxpayers with a long-term town financial picture prior to annual town meeting.

Ms. Rand said the annual town meeting warrant will contain 54 articles.