(3) Valuation correction shall consist of minus one dollar for each one thousand dollars or part thereof that the project area per capita full value is less than the average per capita full value for the state excluding all cities. For projects wholly located within a village or town the project area per capita full value shall be the per capita full value for the village, or for the town outside of village area, respectively. For other projects, per capita full value shall be per capita full value of the town or village within which the major portion of the project is located. Per capita full value shall mean the full value of such municipality or area divided by the population thereof. The amount of such state aid shall be recomputed each year, on the basis of data reported by the local governing body as accepted by the commissioner. State aid shall commence in the state fiscal year beginning April 1, l971. No state-aid payments shall be made on the basis of any portion of the debt service of eligible projects which was due and payable prior to April 1, 1971.