The commissioner, in addition to the annual assessment, shall collect from each bank authorized to engage in the trust business, to defray the cost of examination, a fee not to exceed seventy-five dollars ($75) per hour for each examiner necessarily engaged in the examination of the trust company, trust business, or trust department. The commissioner shall assess the fee upon completion of the examination of the trust company or trust business and shall mail or otherwise deliver an
invoice for the fee to the institution. The institution shall pay the fee within 30 days after the invoice is mailed or otherwise delivered to it.