As soon as practicable after the completion of the record, the hearings officer shall render his decision, or submit his report to the Board, as may be appropriate in the case. The decision or report shall be based on the record and shall be in writing. Such decision shall contain a brief statement of (a) the issue or issues raised, (b) the evidence submitted, (c) findings of fact, (d) the decision made, and (e) the reasons therefor. Such report shall contain a statement of (1) the issue or issues raised, (2) the evidence submitted, (3) findings of fact, (4) conclusions of law, (5) recommendations as to the decision to be made by the Board, and (6) such discussion of the foregoing as the hearings officer may desire to present to the Board. Within 15 days after rendition of the decision or submission of the report, a copy of the decision or report shall be mailed to each party at the last address of record. In the case of a report, a copy of the transcript of the hearing, if any was held, shall also be mailed to each party.