‘ 3. Fee. The fee charged by a title insurer for closing or settlement protection coverage must be filed with the superintendent pursuant to section 2304-A. The fee may not be subject to any agreement requiring a division of fees or premiums collected on behalf of the title insurer. A title insurer may charge only one fee for a closing or settlement protection letter for the protection of all parties receiving the benefit of closing or settlement protection in connection with the real property transaction giving rise to the issuance of the closing or settlement protection letter.’