The commissioner shall not make any order under the provisions of this article without giving every rating organization and insurer who may be affected thereby reasonable notice and a hearing, if hearing is requested. All hearings provided for in this article shall be held at such time and place as shall be designated in a notice which shall be given in writing by registered or certified mail to such rating organization and insurer, or the officers, agents, and representatives thereof, which may be affected thereby, at least 30 days before the date designated therein, which notice shall state the subject of the order. At the conclusion of such hearing, or within 30 days thereafter, the commissioner shall make such order, or orders, as he may deem necessary in accordance with his findings.