The rules set forth in this subpart are applicable only to proceedings forwarded pursuant to § 12.26(b). The rules in subpart B of this part permitting discovery are applicable in a summary decisional proceeding. Unless specifically made applicable, the rules prescribed in subparts C and E of this part shall not apply to such proceedings. Parties to a proceeding forwarded pursuant to § 12.26(b) may, by signed agreement filed at any time prior to the issuance of the initial decision, or of any other order disposing of all issues in the proceeding, elect to have all of the issues in the proceeding decided pursuant to the voluntary decisional procedure. Upon receiving a timely filed stipulation signed by all parties evidencing such an election, the Administrative Judge shall conduct the proceeding and render a decision pursuant to subpart C of this part.