(a) If at any time the assets of a domestic mutual insurer are less than its liabilities and the minimum amount of surplus required to be maintained by it under this title for authority to transact the kinds of insurance being transacted and the deficiency is not cured from other sources, its directors shall levy an assessment only upon its members who held policies providing for contingent liability at any time within the 12 months preceding the date notice of such assessment was mailed to them, and such members shall be liable to the insurer for the amount so assessed.
(b) The assessment shall be for such an amount as is required to cure such deficiency and to provide a reasonable amount of working funds above such minimum amount of surplus, but such working funds so provided shall not exceed five percent of the insurer's liabilities as of the date as of which the amount of such deficiency was determined.
(c) In levying an assessment on a policy providing for contingent liability, the assessment shall be computed on a basis of premium earned on such policy.
(d) No member shall have an offset against any assessment for which he is liable on account of any claim for unearned premium or loss payable.
(e) As to life insurance, any part of such an assessment upon a member which remains unpaid following notice of assessment, demand for payment, and lapse of a reasonable waiting period as specified in such notice may, if approved by the commissioner as being in the best interests of the insurer and its members, be secured by placing a lien upon the cash surrender values and accumulated dividends held by the insurer to the credit of such member.