With West Tisbury footing the majority of the bill, the up-Island Regional School District committee voted on Monday night to certify an $8.35 million budget for next year, a 2.1 per cent increase over last year.

Discussion centered on the possibility of a new kindergarten-first grade class at the Chilmark School and the resulting 4.53 per cent increase in West Tisbury’s $5.8 million assessment compared with a decrease in assessments for Aquinnah and Chilmark. Even without the additional class, West Tisbury’s assessment would still be up 3.99 per cent.

Assessments are based on an enrollment census taken every Oct. 1, and with more West Tisbury students attending the Chilmark and West Tisbury schools, the town’s assessment goes up accordingly. Aquinnah will pay $563,383 and Chilmark will pay $1.9 million. There are currently 311 students enrolled in the district.

“Our population evaluation is this year’s population which will then affect next school year’s assessments,” committee chairman Dan Cabot explained. “We’re expecting there will be a jump in Chilmark School enrollment for [fiscal year] 2012, but the problem is that we’re not assessing Chilmark for those kids because it’s the Oct. 1, 2010, population that drives these numbers.”

Chilmark will not know until next spring at the earliest whether an additional class will be necessary. If a new class is not needed, the $138,000 budgeted for a new teacher, assistant teacher and supplies will go into the district’s excess and deficiency fund.

Vineyard schools superintendent Dr. James H. Weiss met with Chilmark School principal Susan Stevens, West Tisbury principal Donna Lowell-Bettencourt and business administrator Amy Tierney to determine if positions could be moved around within the district, but could not find a compromise.

“The formula is set up the best it could . . . we can’t change expenses, we’re charged with the issue of educating kids the best you can in this district,” Chilmark selectman Frank Fenner said at the meeting. “Unfortunately there’s a question here you won’t know the answer to until April or May.”

Other increases in the budget can be tracked to contract-driven step salary increases and a new guidance counselor at the West Tisbury School.

“We’re supposed to help kids intervene with learning difficulties and target specific things early on and eventually keep less kids off of special education,” Mrs. Lowell-Bettencourt said. “The counselors are the ones that drive that process.

“Kids are really coming to school with stress that gets in the way of their learning,” she continued. “Coupled with that, we’re seeing families who aren’t able to get needs met outside of school,” the principal said.

The committee also voted to use the regional assessment method, which requires all three towns to approve the budget at their annual town meetings in April.

In other news, Mrs. Lowell-Bettencourt and assistant superintendent Laurie Halt announced that the West Tisbury eighth grade class ranked first in the state for MCAS scores out of 283 districts.