By July 15 of 1997 and each subsequent year, the auditor of each county in the area shall determine the amount, if any, by which the net tax capacity determined in the preceding year pursuant to section 276A.03, of commercial-industrial property subject to taxation within each municipality in the county exceeds the net tax capacity in 1995 of commercial-industrial property subject to taxation within that municipality, including the total net tax capacity of property that becomes taxable under section 298.25. If a municipality is located in two or more counties within the area, the auditors of those counties shall certify the data required by section 276A.03 to the county auditor responsible for allocating the levies of that municipality between or among the affected counties. That county auditor shall determine the amount of the net excess, if any, for the municipality under this section, and certify that amount under section 276A.05. The increase in total net tax capacity determined by this section must be reduced by the amount of any decreases in the net tax capacity of commercial-industrial property resulting from any court decisions, court-related stipulation agreements, or abatements for a prior year, and only in the amount of such decreases made during the 12-month period ending on May 1 of the current assessment year, where the decreases, if originally reflected in the determination of a prior year's net tax capacity under section 276A.03, would have resulted in a smaller contribution from the municipality in that year. An adjustment for the decreases shall be made only if the municipality made a contribution in a prior year based on the higher net tax capacity of the commercial-industrial property.