Every dealer shall maintain and keep, for a period of three years, all records of motor vehicle fuel used, sold and distributed within the city by such dealer, together with stock records, invoices, bills of lading and other pertinent papers as may be required by the tax administrator. In the event such records are not kept within the state of Oregon, the dealer shall reimburse the tax administrator for all travel, lodging, and related expenses incurred by the tax administrator in examining such records. The amount of such expenses shall be assessed in addition to the tax imposed by section 3.466.