Rulings of law judges on motions which are not dispositive of the proceeding as a whole may not be appealed to the Board prior to its consideration of the entire proceeding, except in extraordinary circumstances and with the consent of the law judge who made the ruling. Interlocutory appeals shall be disallowed unless the law judge finds, either orally on the record or in writing, that to allow such an appeal is necessary to prevent substantial detriment to the public interest or undue prejudice to a party. If an interlocutory appeal is allowed, any party may file a brief with the Board within such time as the law judge directs. No oral argument will be heard unless the Board directs otherwise.