(a) A petition for reconsideration may be filed by any interested person within 20 days after the date of service of a Board decision which results in an order for:
(1) Investigation and suspension of collective ratemaking actions, or
(2) Investigation (without suspension) of collective ratemaking actions.
(b) Any interested person may file and serve a reply to any petition for reconsideration permitted under paragraph (a) of this section within 20 days after the filing of such petition with the Board, but if the facts stated in any such petition disclose a need for accelerated action, such action may be taken before expiration of the time allowed for reply. In all other respects, such petitions and replies thereto will be governed by the rules of general applicability of the Rules of Practice.