If after a hearing on a complaint made by any person under section 499f of this title, or without hearing as provided in subsections (c) and (d) of section 499f of this title, or upon failure of the party complained against to answer a complaint duly served within the time prescribed, or to appear at a hearing after being duly notified, the Secretary determines that the commission merchant, dealer, or broker has violated any provision of section 499b of this title, he shall, unless the offender has already made reparation to the person complaining, determine the amount of damage, if any, to which such person is entitled as a result of such violation and shall make an order directing the offender to pay to such person complaining such amount on or before the date fixed in the order. The Secretary shall order any commission merchant, dealer, or broker who is the losing party to pay the prevailing party, as reparation or additional reparation, reasonable fees and expenses incurred in connection with any such hearing. If, after the respondent has filed his answer to the complaint, it appears therein that the respondent has admitted liability for a portion of the amount claimed in the complaint as damages, the Secretary under such rules and regulations as he shall prescribe, unless the respondent has already made reparation to the person complaining, may issue an order directing the respondent to pay to the complainant the undisputed amount on or before the date fixed in the order, leaving the respondent’s liability for the disputed amount for subsequent determination. The remaining disputed amount shall be determined in the same manner and under the same procedure as it would have been determined if no order had been issued by the Secretary with respect to the undisputed sum.