17-5-301. Refunding bonds or debentures authorized -- interest rate. The board of examiners is hereby authorized and empowered to refund any issue of bonds, highway or other debentures heretofore issued by the state and which are outstanding or which may hereafter be issued by the state whenever in the judgment of such board it shall be deemed for the best interests of the state to do so. Refunding bonds or debentures shall not be issued in any greater amount than will be required to pay the principal and interest of the bonds or debentures to be refunded, costs of issuance, plus any defaulted interest thereon.