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.