Notwithstanding subdivision (a) of Section 50401, if the commissioner determines that the charges and assessments set forth in this division for any year are in excess of the amount necessary, or are insufficient, to meet the expenses of administration of this division for that year, the assessments and charges for the following year shall be adjusted on a pro rata basis in accordance with the percentage of the excess or insufficiency as related to the actual charges

and assessments for the year for which the excess or insufficiency occurred, in order to recover the actual costs of administration and provide a prudent reserve of 90 days’ costs and expenses.