(1) A refunding of outstanding obligations of a public body may be accomplished pursuant to this article by the issuance of bonds for refunding, paying, and discharging all or any part of such outstanding obligations, including a portion of one or more issues of such obligations and including any interest thereon in arrears or about to become due, and for one or more of the following purposes:

(a) Avoiding or terminating any default in the payment of interest on or principal of, or both interest on and principal of, said obligations;

(b) Reducing the net effective interest rate of said obligations;

(c) Reducing total interest payable over the life of the obligations, by issuing bonds of a shorter term, or at a lower net interest cost, or having a lower net effective interest rate;

(d) Reducing the total principal and interest payable on such obligations or the principal and interest payable thereon in any particular year or years, or affecting other economies;

(e) Modifying or eliminating restrictive contractual limitations appertaining to such obligations, to the incurring of additional indebtedness or obligations, or to any system, facility, or improvement appertaining thereto;

(f) Postponing the maturity of all or any part or portion of said obligations to a later date, subject to the limitations in section 11-56-107;

(g) Substituting an issue of bonds for a note or notes, or other obligations, including but not limited to any obligation issued in anticipation of the later issuance of bonds;

(h) Any combination of the foregoing purposes specified in this subsection (1).

(2) In making the computations necessary or appropriate pursuant to subsection (1) of this section for a refunding transaction in which all or any portion of the principal of or interest on the refunding bonds is to be paid from the proceeds of such refunding bonds or the interest or other income to be derived from the investment of such proceeds, including any refunding transaction as a part of which special obligation refunding bonds are to be issued, only those amounts with regard to bonds issued for refunding purposes which are to be payable by the public body from sources other than refunding bond proceeds and the interest and other income derived from the investment of such proceeds need to be considered.