Any county, by and through its county commission, either for and on behalf of the county or for and on behalf of any magisterial district or group of magisterial districts therein; any municipal corporation, by and through its council or other governing body in lieu thereof; or any school district, or any independent school district, by and through its Board of Education or other fiscal body in lieu thereof, may, in the manner and subject to the limitations and conditions contained in this article, issue and sell its bonds for the purpose of refunding the bonds of such political division which have become or are becoming due and payable and for the discharge of which there are or will be when the bonds mature no funds or insufficient funds available; or when, in the opinion of the governing body of the political division obligated to the payment of such bonds, the rate of levy necessary to provide funds for their discharge will impose excessive taxes upon the taxpayers of such political division; or for the purpose of providing for the payment of outstanding bonds in advance of the maturity or redemption thereof through the making of a deposit as provided in section four of this article; or for the purpose of rendering outstanding bonds not due when such outstanding bonds are to be presented for payment before maturity by the exercise of option provisions or by agreement with the holders thereof. Such refunding bonds may be issued bearing the same or a higher or lesser rate of interest than the bonds to be refunded. Except to the extent that additional taxes for such purpose have been approved by the voters and the levy of such additional taxes provided for in the manner stipulated in sections seven through fourteen of article one of this chapter, no such refunding bonds shall be issued bearing a higher rate of interest than the bonds being refunded or shall be issued in a principal amount exceeding the principal amount of the bonds to be refunded unless the amount of debt service payable on such refunding bonds in each year is equal to or less than the amount of taxes expected to be available therefor as shall be certified by the chairman of the West Virginia Municipal Bond Commission prior to the issuance of such refunding bonds. The amount of taxes expected to be available in each year for purposes of this section shall be based upon the rates of levy stipulated in the order directing the election at which the issuance of the bonds being refunded was approved by the voters and upon the most recent assessed valuation of the affected property prior to such election. In the event only a portion of the bonds provided for such order are being refunded or have been issued, an appropriate reduction shall be made in the amount of taxes expected to be available based upon the actual debt service requirements of bonds which have been issued but are not being refunded and the estimated debt service requirements of bonds which have not been issued.