The failure to pay any fee as required by this section shall cause that fee to become delinquent and an additional sum equal to 50% of the fee so required shall be imposed for such delinquency and become a part of the fee required, provided however that the Fire Department, with the approval of the City Attorney, shall waive any or all of said 50% to the extent such exceeds any extra costs caused by said delinquency. The City Attorney may approve waiver of penalty for good cause, based upon information supplied by the business and by the Fire Department. Good cause shall include any adequately documented circumstance of extreme financial hardship arising from the requirement that the 50% penalty be paid. Minor discrepancies in payments, charges for duplicates of permits, and refunds of fees paid shall be administered for purposes of this section in the same manner as provided for permits under Sections 57.106.6.7, 57.106.6.10 and 57.106.6.11.