The parties have 7 days after the close of the hearing, subject to any extension that may have been granted, to file briefs with the Board and to request oral argument which the Board may or may not grant. However, in cases involving the national defense and so designated in the notice of hearing, the parties may not file briefs but after the close of the evidence may argue orally upon the record their respective contentions and positions, except that for good cause shown in an application expeditiously made to the Board in Washington, DC, after the close of the hearing, the Board may grant leave to file briefs in such time as it shall specify. The Board then considers the evidence taken at the hearing and the hearing officer's analysis together with any briefs that may be filed and the oral argument, if any, and issues its determination or makes other disposition of the matter.