The schematic design plan for the proposed $131.9 million Winchester High School project has been submitted to the Massachusetts School Building Authority. Superintendent William H. McAlduff Jr. has said he is hopeful the state authority will take action on the plan at its Oct. 2 meeting. If the authority accepts the design and agrees to help fund the project, the town would have 120 days to authorize the full project amount. According to McAlduff, voters would have to approve a debt exclusion, or temporary tax increase, to cover the costs. Ultimately, the superintendent expects the School Building Authority to reimburse the town for roughly one-third of the project’s eligible expenses. The proposal calls for moderate additions and renovations to the Skillings Road high school, which was built in 1971, to address mechanical, plumbing, and electrical deficiencies.