Section 76. The board of survey may from time to time make new plans in place of plans filed in accordance with the two preceding sections, or make changes on plans so filed; provided, that any action involving new plans or changes in plans already duly attested and filed shall be made only after the notice and hearing, and in all other respects in the manner specified in section seventy-four; and the last plan so made, or the plan with the changes last made thereon and duly attested and filed, shall be the plan governing the future development of the territory affected.