During the last one-half (1/2) of the impact period and for not to exceed three (3) years thereafter, each taxpayer who has prepaid taxes shall be allowed a credit for such taxes paid during the first one-half (1/2) of the impact period. The credit shall be allowed against the actual taxes assessed to the taxpayer by the taxing district which received prepaid taxes from the local impact fund, and shall be calculated to provide an approximately equal credit during each year that the credit is allowed. Any extension of time during which the credit may be allowed shall require the approval of the local impact committee.