(A) All final orders and decisions of the commission must be sufficient in detail to enable the court on appeal to determine the controverted questions presented in the proceedings and must include:
(1) findings and conclusions, and the reasons or bases therefor, upon all the material issues of fact or law presented in the record; and
(2) the appropriate rule, order, sanction, relief, or statement of denial thereof.
(B) A copy of every final order or decision under the seal of the commission must be served by registered or certified mail upon all parties to the proceeding or their attorneys. Service upon a party or upon the attorney must be made by mailing a copy to him at his last known address. If no address is known, however, service shall be made by leaving a copy with the chief clerk of the commission. The order takes effect and becomes operative when served unless otherwise designated and continues in force either for a period designated by the commission or until changed or revoked by the commission. If, in the judgment of the commission, an order cannot be complied with within the time designated, the commission may grant and prescribe additional time as is reasonably necessary to comply with the order and, on application and for good cause shown, may extend the time for compliance fixed in its order.