A carrier may file with the chairman, not later than the 10th day prior to the date set for hearing, a withdrawal of objection on a form (A-3) prescribed by the chairman for that purpose, in which event the chairman will refund to the chiropractor the $5 expense fee paid by him. If the parties to the dispute settle their differences within 10 days prior to the date set for hearing, notice of settlement on a form (A-4) prescribed by the chairman for that purpose shall be signed by all parties and filed with the chairman on or before the date set for hearing. The parties to such a settlement shall each pay to the chairman a minimum expense fee of $5 in the manner provided in section 347.8 of this Part.