Except as provided in § 4.809(e), a ruling of the administrative law judge may not be appealed to the Director, Office of Hearings and Appeals, prior to consideration of the entire proceeding by the administrative law judge unless permission is first obtained from the Director, Office of Hearings and Appeals, and the administrative law judge has certified the interlocutory ruling on the record or abused his discretion in refusing a request to so certify. Permission will not be granted except upon a showing that the ruling complained of involves a controlling question of law and that an immediate appeal therefrom may materially advance the final decision. An interlocutory appeal shall not operate to suspend the hearing unless otherwise ordered by the Director, Office of Hearings and Appeals. If an appeal is allowed, any party may file a brief within such period as the Director, Office of Hearings and Appeals, directs. Upon affirmance, reversal, or modification of the administrative law judge's interlocutory ruling or order, by the Director, Office of Hearings and Appeals, the case will be remanded promptly to the administrative law judge for further proceedings.