Notice of the order shall be sent by registered or certified mail to the State or local agency from which the amount is ordered to be withheld. After the order becomes final, the Federal agency to which the order is certified shall withhold the amount in accordance with the terms of the order. Except as provided by
section 1508 of this title, a determination or order of the Board becomes final at the end of 30 days after mailing the notice of the determination or order.