(a) Premium rates for the insuring or guaranteeing of titles shall not be excessive, inadequate, or unfairly discriminatory.
(b) Each title insurer shall file with the Commissioner a schedule showing the premium rates to be charged by it. Every addition to or modification of such schedule or of any rate therein contained shall likewise be filed with the Commissioner, and no such addition or modification shall be effective until expiration of 15 days of such filing.
(c) The Commissioner may order the modification of any premium rate or schedule of premium rates found by him after a hearing to be excessive, or inadequate, or unfairly discriminatory. No such order shall require retroactive modification.