At the conclusion of the evidentiary portion of the hearing and after hearing such final argument as the Hearing Committee Chair shall permit, the Hearing Committee shall go into executive session and decide preliminarily whether it finds a violation of any disciplinary rule has been proven by Bar Counsel. In all cases in which the Hearing Committee is able to reach such a preliminary, non-binding determination, the Hearing Committee shall immediately resume the hearing and permit Bar Counsel to present evidence of prior discipline, if any. Respondent shall be permitted to present any additional evidence in mitigation. In those extraordinary cases where the Hearing Committee is unable to reach such a preliminary determination, the Hearing Committee Chair may defer the presentation of matters in aggravation (including prior discipline) and in mitigation until such later time as the Hearing Committee Chair shall designate for the presentation of such evidence in documentary form or at a subsequent hearing which the Hearing Committee Chair may authorize on a showing of good cause.