Compensation payable to guardians shall be based upon services rendered and shall not exceed five percent of the amount of moneys received during the period covered by the account, except that the court may allow a fee of not exceeding twenty-five dollars per year, as a minimum fee, upon the approval of the chief attorney for the veterans administration. In the event of extraordinary services by any guardian, the court, upon petition and hearing thereon may authorize reasonable additional compensation therefor. A copy of the petition and notice of hearing thereon shall be given the proper office of the veterans administration in the manner provided in the case of hearing on a guardian's account or other pleading. No commission or compensation shall be allowed on the moneys or other assets received from a prior guardian nor upon the amount received from liquidation of loans or other investments.