The presiding officer may, when all parties have rested, present such evidence, in addition to that presented by the parties, as deemed necessary to decide the appeal fairly and equitably. Any such evidence secured and presented by the presiding officer shall be presented in an impartial manner, and shall be received subject to full opportunity for cross-examination by all parties. If a party desires to present rebuttal evidence to any evidence so presented by the presiding officer, application shall be made therefor immediately following the conclusion of such evidence. Such application shall be granted by assignment of a time and place for presentation of such rebuttal evidence.