Unless on notice and opportunity for all parties to participate, or to the extent required for the disposition of ex parte matters as authorized by Sections 7308(c), 7309(c), 7316(c) and/or 7325(c) of the Act:

(a) No party, or counsel to or representative of a party, shall make or knowingly cause to be made an ex parte communication relevant to the merits of a proceeding to the administrative hearing officer with respect to that proceeding.

(b) No administrative hearing officer with respect to a proceeding shall make or knowingly cause to be made to a party, or counsel to or representative of a party, an ex parte communication relevant to the merits of that proceeding.