(a) If further facilities or services are authorized to be financed by the district, savings achieved through the issuance of refunding bonds may be used by the legislative body for those purposes.
(b) If no further facilities or services are authorized to be financed by the district, any savings achieved through the issuance of refunding bonds shall be used by the legislative body to reduce the special taxes levied to retire outstanding bonds.
(c) Savings achieved through the issuance of refunding bonds may be used pursuant to both subdivisions (a) and (b) in proportions determined by the legislative body.
(d) For purposes of this section, the terms “savings achieved through the issuance of refunding bonds” means the difference between the principal and interest to maturity of the refunded bonds and the principal and interest to maturity of the refunding bonds.
(e) If savings are to be used for authorized facilities, bonds may be issued that are secured by that savings.