The plan shall file in the office of the insurance commissioner annually on or before the fifteenth day of March, a statement which shall contain information with respect to its transactions, conditions, operations and affairs during the preceding year. Such statement shall contain such matters and information as are prescribed and shall be in such form as is approved by the insurance commissioner. The insurance commissioner may, at any time, require the plan to furnish additional information with respect to its transactions, condition, or any matter connected therewith considered to be material and of assistance in evaluating the scope, operation and experience of the plan.