Parties may request appearance of witnesses and production of documents by filing application therefor, depending upon the stage of the proceedings at which the request is made, with the officer conducting the investigation or hearing, or with the panel. Such application shall name and identify the witnesses or documents sought and shall briefly state the need for such appearance or production. The officer with whom such request is filed shall rule upon each such request and the record of the proceeding shall contain a record of that ruling and the basis therefor. The record shall also contain a statement of reasons for any request for the appearance of witnesses or production of documents initiated by a presiding officer.