If temporary rates are prescribed under N.H. Rev. Stat. § 378:27 which are higher than those previously in effect, the commission may require the public utility to file a bond in such form and with such sureties, if any, as the commission may determine, to secure the repayment to the customers of the public utility of the difference between the amounts collected under such temporary rates and the rates which the commission finds should have been in effect during the continuance of such temporary rates.