In those cases where the net assessed valuation of the real property within a school district increases as a result of the provisions of Sections 860 and 861 of this title, the school district's State Aid shall be determined by subtracting such increase in the net assessed valuation from the assessed valuation of the school district and the state. Such increase shall be subtracted for each fiscal year during which the incentives or exemptions are granted in the case of property within an incentive district or such increase shall be subtracted for each fiscal year the increment is captured in the case of property within an increment district. The increase in net assessed valuation subtracted, in the case of property within an increment district, shall be the amount that represents that portion of the increment which is captured and which is actually used for the purposes of this act.¹