(1) The net retained liability of a title insurer for a single risk in regard to property, whether assumed directly or as reinsurance, shall not exceed the aggregate of fifty percent of surplus as regards policyholders plus the statutory premium reserve less the title insurer's investment in title plants, all as shown on the most recent annual statement of the title insurer on file with the director.

(2) For purposes of the Title Insurers Act:

(a) A single risk shall be the insured amount of any title insurance policy, except that when two or more title insurance policies are issued simultaneously covering different estates in the same real property, a single risk shall be the sum of the insured amounts of all the title insurance policies; and

(b) A title insurance policy under which a claim payment reduces the amount of title insurance under one or more other title insurance policies shall be included in computing the single risk sum only to the extent that its amount exceeds the aggregate amount of the title insurance policy or policies whose amount of title insurance is reduced.