Where an appraisal fee is charged under Section 18216 of the Financial Code, the actual cost of an appraisal of real property shall be supported by a worksheet which shows the hours spent in connection with the appraisal, the hourly rates of the appraisers and other employees and any other direct costs. A composite hourly rate for appraisers or other employees may be used with the written consent of the Commissioner. Overhead expenses shall not be included in actual costs.