The conducting of the same business at two or more separate premises within the district shall, for the purposes hereof, be deemed to be separate businesses and each such business shall be subject to the assessment herein provided for. If two or more separate but related businesses are conducted on the same premises by the same owners, one special assessment shall be paid for the business to which the premises are primarily appropriated but shall be based upon the assessment for all businesses within the premises except that only one minimum amount shall be paid, minimum amount being the first forty dollars ($40.00) due under any assessment formula. (Prior code § 5.80.110)