Compensation orders shall become effective when filed in the office of the district director, and unless proceedings for suspension or setting aside of such orders are instituted within 30 days of such filing, shall become final at the expiration of the 30th day after such filing, as provided in section 21 of the Act 33 U.S.C. § 921. If any compensation payable under the terms of such order is not paid within 10 days after it becomes due, section 14(f) of the Act requires that there be added to such unpaid compensation an amount equal to 20 percent thereof which shall be paid at the same time as, but in addition to, such compensation unless review of the compensation order is had as provided in such section 21 and an order staying payment has been issued by the Benefits Review Board or the reviewing court.