After hearing held pursuant to notice as provided in section three of this article, the governing body, by ordinance or resolution, may authorize such improvements and the assessing of the total cost or any part thereof on abutting property as herein provided. In the same or subsequent ordinances or resolutions, but before advertising for bids from contractors, the governing body shall cause to be prepared plans, specifications and estimates of the cost of the proposed improvements under the supervision of the engineer for the municipality. Such plans, specifications and estimates shall show the proposed grade and sufficient data for any owner of abutting property to calculate approximately what proportionate part of the estimated cost thereof might be assessed against his property, and shall be filed with the recorder and open to the inspection of interested persons before advertisement for bids of contractors and before the meeting at which such bids may be accepted or rejected. Before advertising for bids of contractors, such governing body shall consider said plans, specifications and estimates and may amend or modify them, and before advertising for bids shall by ordinance or resolution approve such plans, specifications and estimates as so amended and modified. Such ordinance or resolution shall also provide for advertisement for bids, for the letting of a contract or contracts for the work to the lowest responsible bidder, with right reserved to such governing body to reject any and all bids, and shall provide for supervision of such work by the mayor, city manager, if any, municipal engineer, if any, or other person or committee designated by the governing body. Such ordinance or resolution shall also provide for payment of the cost of the work when completed. The governing body shall provide in such ordinance or resolution for the payment by abutting property owners of the cost of the work in equal installments payable over a period of not less than five years nor more than ten years from the date of assessment, with interest not to exceed eight percent a year from the date of assessment, and in said ordinance or resolution the governing body shall fix the number of installments in which the amounts assessed shall be payable: Provided, That each of said assessments or the installments thereof then remaining unpaid shall be payable at any time after assessment without interest after the date such payment is made: Provided, however, That on failure of the owner of the property assessed to pay any installment as and when due, and if such default continues for sixty days, then at the option of the governing body (if neither assessment certificates nor bonds are issued as hereinafter in this article provided), or the holder of the assessment certificates (if the assessments are evidenced by such certificates), or the holder of any bonds secured by such assessments (if bonds are issued), the entire balance due may be declared immediately due and payable and the municipality, or the holder of the certificates, or bonds, as the case may be, may forthwith proceed to enforce the collection thereof: Provided further, That if the amounts to be assessed against abutting property be less than $2 for each abutting front foot of property, then said governing body is authorized to make the same payable in one lump sum or in installments, with interest, over a period of less than five years from the date of assessment.