(1) The board will not consider any new evidence introduced at the board hearing unless good cause is shown that it was unavailable at the hearing before the hearing officer. If new evidence is admitted, it must be the type of evidence on which responsible persons are accustomed to rely in the conduct of serious affairs.

(2) If the board finds that additional evidence is required to reach a decision, it may remand the matter to the hearing officer to conduct a hearing to obtain additional evidence in the matter. The board shall promptly notify the interested parties of such action. The hearing officer must make a new decision based on the additional evidence and the existing record.