(a) The Presiding Officer shall submit to the Commission a written decision based upon the evidence and argument presented, within sixty days, not including any period the record is held open, if any, after conclusion of the hearing, unless otherwise extended by the Presiding Officer.

(b) Copies of the Presiding Officer's decision shall be mailed to the Applicant. The Applicant may submit briefs or other written argument to the Commission within fourteen days of the date the Presiding Officer's determination was mailed to the Applicant.