The proportion of the fees which is payable to the department may vary upon a seasonal basis for each program according to the estimated expense to be incurred by the director in administering the marketing program. The amount so required shall not exceed 15 percent of the certificate fees which are collected by the proration zone agent specifically for administrative purposes, however, such 15 percent limit may be exceeded when it is approved by the program committee, and, in addition, such proportion of fees which are collected for any educational and trade stimulation marketing program as may be required by the director to administer the marketing program, which shall in no event exceed 5 percent of the fees which are collected for such purpose, unless the payment of a larger proportion of such funds is approved by the marketing program committee for the marketing program.