All insurers that are members of the plan shall participate in its expenses, profits, and losses in the proportion that the net direct premiums of each such member (excluding that portion of premiums attributable to the operation of the plan) written during the preceding calendar year bears to the aggregate net direct premiums written in this State by all members of the plan. Insurers that are members of the plan may also be appointed by the insurance commissioner as servicing companies to underwrite the medical malpractice insurance. Each insurer’s participation in the plan shall be determined annually on the basis of such net direct premiums written during the preceding calendar year, as reported in the annual statements and other reports filed by the insurer with the insurance commissioner. No member shall be obligated in any one year to reimburse the plan on account of its proportionate share in the deficit from operations of the plan in that year in excess of one per cent of its policyholders’ surplus and the aggregate amount not so reimbursed shall be reallocated among the remaining members in accordance with the method of determining participation prescribed in this section after excluding from the computation the total net direct premiums of all members not sharing in the excess deficit. In the event that the deficit from operations allocated to all members of the plan in any calendar year shall exceed one per cent of their respective policyholders’ surplus, the amount of such deficit shall be allocated to each member in accordance with the method of determining participation prescribed in this section.