None of the fees or regulations provided for by this chapter shall be so applied as to occasion an undue burden upon interstate commerce. In any case where a fee, order, or requirement is believed by a railroad company to place an undue burden upon such commerce, the company may apply to the mayor for an adjustment of the fee, or alteration of the order or requirement so as not to be discriminatory, unreasonable, or unfair as to such commerce. Such application may be made before, at, or within six months after payment of the prescribed fee, or within 90 days after any order or requirement made after hearing thereon. The applicant shall by affidavit and supporting testimony and evidence give and show such information relating to applicant’s business and such other information as the mayor may deem necessary in order to determine the extent, if any, of undue burden on such commerce. The mayor shall then conduct an investigation, considering all the information and evidence presented, and shall make findings of fact from which he shall determine whether the fees fixed by this chapter, and regulations of the board of public works as provided by this chapter, are unfair, unreasonable, or discriminatory as to applicant’s business and shall fix the fees for the applicant in an amount that is fair, reasonable, and nondiscriminatory; or, if the fee has already been paid, shall order a refund of the amount over and above the fee so fixed, and order alterations of orders of the board of public works so that they are not unreasonable, discriminatory, or unfair as to interstate commerce. [Code 1980 at § 11.20.070].