Notwithstanding any section of chapter 40-23, the city auditor shall determine, on the basis that the special benefit conferred upon a lot, tract, or parcel of land in the improvement district, by the establishment of a parking lot, is proportionate to the need that the business conducted thereon has for a parking lot, the amount which each lot, tract, or parcel of land will be especially benefited by the construction of the work for which such special assessment is to be made, and shall assess against each lot, tract, or parcel of land such sum, not exceeding the benefits, as shall be necessary to pay its just proportion of the total cost of such work, or of the part thereof which is to be paid by special assessment, including all expenses incurred in making such assessment and publishing necessary notices with reference thereto. Such action shall be subject to the final approval of the governing body which may increase or diminish any of such assessments as it may deem just.