The mutual company may insert in any form of policy prescribed by the law of this state any provisions or conditions required by its plan of insurance that are not inconsistent or in conflict with any law of this state. The policy, in lieu of conforming to the language and form prescribed by the law, may conform thereto in substance, if the policy includes a provision or endorsement reciting that the policy shall be construed as if in the language and form prescribed by the law, and a copy of the policy and endorsement, if any, has been first filed with, and has not been disapproved by, the commissioner.