A property broker who engages in another business, whether as a carrier, warehouseman or otherwise, shall keep and maintain his records in a manner that the revenues and expenses pertaining to his brokerage operations will be separated from those of his other operations. Expenses that are common to his brokerage and other operation shall be allocated to each on an equitable basis, and the broker shall be prepared to show and to report to the Commission when required the allocation of the common expenses and the basis of the allocations.
52 Pa. Code § 39.14