(a) Where the approved budget exceeds the allocation to the intermediate unit, each school district within the intermediate unit shall contribute to the intermediate unit a share of the amount by which the budget exceeds the allocation, computed in the following manner: (1) Determine a weight factor for each school district by multiplying the school district's weighted average daily membership by the difference between 1.0000 and the school district's aid ratio; (2) determine a value per weight factor for the intermediate unit by dividing the amount by which the budget exceeds the allocation by the total weight factors of all school districts comprising the intermediate unit; and (3) determine each school district's share by multiplying the value per weight factor by the weight factor of the school district.

(b) Less than a majority of the school districts comprising an intermediate unit may contract with the intermediate unit for services to be provided for the contracting school districts by the intermediate unit, with the cost of such services to be paid by the contracting school districts in such manner as they may agree upon.

(c) If a school district desires to independently provide a service that is included in the approved program of services to be offered by an intermediate unit, and the service is to be financed solely by the school district, and if the intermediate unit board of directors determines that the quality of such service is adequate and that such independent action will not adversely affect the service to be offered to the remaining districts by the intermediate unit, the intermediate unit board of directors may relieve the school district of payment for such service.

(d) Payments due from school districts to an intermediate unit shall be withheld by the Commonwealth from subsidies payable to school districts during November and paid to the intermediate unit not later than January 1 each year.