"Regional reimbursable expenditures", the total amount expended by a regional school district during a fiscal year for the support of public schools during said year exclusive of expenditures for transportation, for food for school food service programs and for capital outlays, after deducting therefrom any receipts for tuition, receipts from the federal government, the proceeds of any invested funds, and grants, gifts and receipts from any other source, to the extent that such receipts are applicable to such expenditures; provided, however, that in the first year that a regional school district is formed or the year in which a regional school district expands "regional reimbursable expenditures" shall mean the total amount expended by a regional school district in the fiscal year during which time the regional school district becomes operative or during which time the regional school district expands for the support of the public schools during said year exclusive of expenditures for transportation, for food for school food service programs, and for capital outlays, after deducting therefrom any receipts for tuition, receipts from the federal government, the proceeds of any invested funds and grants, gifts and receipts from any other source, to the extent that such receipts are applicable to such expenditures; provided however that amounts received by a regional school district under this section as school aid shall not be so deducted. The commissioner of education may, by regulation, further define the expenditures and receipts that may be included hereunder.
"Regional school aid percentage," the amount by which one hundred per cent exceeds the product, to the nearest tenth of one per cent, of sixty-five per cent multiplied by the regional valuation percentage; provided, however, that in no instance shall the regional school aid percentage be less than fifteen per cent.
"Regional valuation percentage," the proportion, to the nearest tenth of one per cent, which the total equalized valuation of all cities and towns in the regional school district divided by the total school attending children in all cities and towns in the district bears to the average equalized valuation per school attending child in the cities and towns in regional school districts in the entire state.
In the event that all of the member communities of a partial regional school district should vote on or before July first of any year to amend their regional school district agreement to allow for expansion into a full kindergarten through twelve regional school district on or before September fifteenth of that same calendar year, then such expanded regional school district shall be entitled to receive, subject to appropriation, on or before November twentieth of that same calendar year, twenty-five per cent of an amount of regional school aid calculated upon the basis of an existing kindergarten through twelve regional school district. The regional school aid shall be computed in accordance with the provisions of this section. For purposes of this paragraph, regional reimbursable expenditures shall mean the total amount expended by the partial regional school district and the member communities for the support of their public schools during the fiscal year in which expansion is voted, minus the exclusions currently provided for in this section.
Mass. Gen. Laws ch. 71, § 16D