(1) Assessments may be levied from time to time upon the subscribers of a domestic reciprocal insurer, other than as to nonassessable policies, by the attorney upon approval in advance by the subscribers' advisory committee and the commissioner; or by the commissioner in liquidation of the insurer.

(2) Each such subscriber's share of a deficiency for which an assessment is made, not exceeding in any event his or her aggregate contingent liability as computed in accordance with RCW 48.10.290, shall be computed by applying to the premium earned on the subscriber's policy or policies during the period to be covered by the assessment, the ratio of the total deficiency to the total premiums earned during such period upon all policies subject to the assessment.

(3) In computing the earned premiums for the purposes of this section, the gross premium received by the insurer for the policy shall be used as a base, deducting therefrom solely charges not recurring upon the renewal or extension of the policy.

(4) No subscriber shall have an offset against any assessment for which he or she is liable, on account of any claim for unearned premium or losses payable.