None of the license fees provided for by subsection 3-1-5A of this chapter shall be applied as to occasion an undue burden on interstate commerce. In any case, where a license fee is believed by a licensee or applicant for license to place an undue burden upon such commerce, he may apply to the license assessor and collector for an adjustment of the fee so that it shall not be discriminatory, unreasonable or unfair as to such commerce. Such application may be made before, at or within six (6) months after payment of the prescribed license fee. The applicant shall, by affidavit and supporting testimony, show his method of business and the gross volume or estimated gross volume of business and such other information as the license assessor and collector may deem necessary in order to determine the extent, if any, of such undue burden on such commerce. The license assessor and collector shall then conduct an investigation, comparing applicant's business with other businesses of like nature and shall make findings of fact from which he shall determine whether the fee fixed by subsection 3-1-5A of this chapter is discriminatory, unreasonable or unfair as to applicant's business and shall recommend to the governing body a license fee for the applicant in an amount that is nondiscriminatory, reasonable and fair, and if the governing body is satisfied that such license is the amount that the applicant should pay, it shall fix the license fee in such amount. If the regular license fee has already been paid, the governing body shall order a refund of the amount over and above the fee fixed by the governing body. In fixing the fee to be charged, the license assessor and collector shall have the power to base the fee upon a percentage of gross sales, or employees, or may use any other method which will assure that the fee assessed shall be uniform with that assessed on businesses of like nature. (1991 Code § 5.04.150, as amended; amd. 2009 Code)