If all creditors sign a written agreement so to do, the debtor may be paid more than the amounts herein provided for. If the petitioner is required by an order of a court of competent jurisdiction to pay money for the support and maintenance of children, then upon the filing with the court of a certified copy of the order, there shall be exempted such further sum as may be required to comply with the order, which the clerk shall forward to the person or official named in the order to receive the same.