(a) In order to facilitate the refunding of its bonds, any county issuing refunding bonds may issue certificates of indebtedness bearing interest not to exceed five percent (5%) per annum, payable to bearer and negotiable, to cover matured interest due on outstanding bonds at the time they are exchanged for refunding bonds and may issue certificates of indebtedness, not bearing interest, payable to bearer, and negotiable, to cover the expenses of issuing refunding bonds.
(b) Both classes of certificates shall be paid out of the bond fund account of the county from any surplus that remains in the bond fund account in any year after the payment of the full amount of bonds and interest due that year on the refunding issue.
(c) Both classes of certificates of indebtedness issued in connection with an issue of refunding bonds shall be registered by the county treasurer, except that the certificates for expenses shall bear the early registration numbers to be followed by the certificates for interest. The certificates for interest shall be paid in numerical order of registration out of the money available for their payment.