The Comptroller may pay out of the state treasury the premiums on the surety bonds of all state officials who are required to be bonded, for a period of more than one year when a discount for advanced payment of the premiums may be obtained under the rates, and regulations adopted by the State Corporation Commission according to law. If any such surety bond is cancelled prior to its expiration, the portion of the premium to be returned shall be calculated on the basis of the regular annual rate of premiums for the duration of the bond as such refunds are prescribed by the rates, and regulations adopted by the State Corporation Commission according to law.