Section 16D. (a) A regional school district shall be entitled to receive state aid for construction of regional schools. Each city or town in a regional school district whether established under special or general law shall continue to receive such state aid for educational purposes as it would be entitled to receive if such district had not been formed. In addition, the state treasurer shall, subject to the provisions of subsection (c), upon certification by the commissioner of education annually pay on or before November twentieth to each regional school district an amount computed as follows:

(i) seventy per cent multiplied by the product of the regional school aid percentage multiplied by the regional reimbursable expenditures of the regional school district, for such districts which include grades kindergarten through twelve; or

(ii) fifty per cent multiplied by the product of the regional school aid percentage multiplied by the regional reimbursable expenditures of the regional school district, for all other regional school districts.

(b) The definitions in section two of chapter seventy shall apply to this section and the following words and phrases as used in this section shall have the following meanings:—

''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.

(c) The receipt of the regional school aid as set forth in clauses (i) and (ii) of subsection (a) shall be subject to the following conditions:

(i) the formation of new regional school districts and the expansion of currently existing regional school districts shall be subject to the approval of the commissioner of education;

(ii) except as provided in clause (iii) of this subsection, no regional school aid shall be paid prior to the date of award of a contract for the construction of a regional school by the regional district school committee or prior to the date the regional district school committee enters into a lease of land and buildings or portions of buildings in lieu of such construction; and

(iii) in the case of regional school districts formed for administrative purposes only, no regional school aid shall be paid prior to the date on which the regional school district has assumed jurisdiction over the pupils in the district and the commissioner of education has made a determination that member cities and towns have provided sufficient and adequate school facilities for each grade level included in the regional school district.

(d) In the event that the member communities of a proposed regional school district should vote on or before July first of any year to establish a regional school district on or before September fifteenth of that same calendar year, then such 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 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 member communities for the support of public school students who will be served by the newly established regional school district, during the fiscal year in which the member communities voted to establish the regional school district, minus the exclusions currently provided for in this section.

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.

(e) Notwithstanding the foregoing provisions of this section, for the fiscal year ending on June thirtieth, nineteen hundred and ninety-four, regional schools shall receive the same amount of state aid that they received in the fiscal year ending on June thirtieth, nineteen hundred and ninety-three; provided, however, that any regional school that received in the fiscal year ending on June thirtieth, nineteen hundred and ninety-three less than seventy-six percent of the amount of state aid that it would have been entitled to pursuant to the foregoing provisions of this section if the full amount had been appropriated for such state aid in said fiscal year nineteen hundred and ninety-three shall receive an additional state aid payment in fiscal year nineteen hundred and ninety-four such that the total state aid for each regional school pursuant to this section shall be no less than seventy-six percent of the amount of state aid that it would have been entitled to pursuant to the foregoing provisions of this section if the full amount had been appropriated for such state aid in said fiscal year nineteen hundred and ninety-three; provided, further, that any regional school district that is newly reorganized pursuant to section fifteen subsequent to June thirtieth, nineteen hundred and ninety-two but prior to January first, nineteen hundred and ninety-four shall receive seventy-six percent of the amount it would otherwise have been entitled to receive for expenses incurred in the first year of operation as a reorganized school district pursuant to the foregoing provisions of this section; provided, further, that any regional school district whose member communities hold meetings on regionalization prior to January first, nineteen hundred and ninety-four and becomes newly organized prior to April first, nineteen hundred and ninety-four shall receive seventy-six percent of the amount it would otherwise have been entitled to receive for expenses incurred in the first year of operation as an organized school district pursuant to the foregoing provisions of this section.

(f) For fiscal years nineteen hundred and ninety-four and subsequent fiscal years, the amount of state aid distributed as base aid pursuant to chapter seventy shall be deemed to be in full satisfaction of the provisions of subsection (e).

(g) Notwithstanding the foregoing provisions, regional bonus aid, but no other aid pursuant to this section, shall be paid to any regional school district formed after fiscal year nineteen hundred and ninety-three for the immediate five fiscal years following the establishment of said regional school district. Regional bonus aid shall be payable in an amount equal to fifty dollars per foundation enrollment, in the first fiscal year following the establishment of said regional school district; forty dollars per foundation enrollment in the second fiscal year following the establishment of said regional school district; thirty dollars per foundation enrollment in the third fiscal year following the establishment of said regional school district; twenty dollars per foundation enrollment in the fourth fiscal year following the establishment of said regional school district; and, ten dollars per foundation enrollment in the fifth fiscal year following the establishment of said regional school district.