When the Commission finds that reparation is due, but that the amount cannot be ascertained upon the record before it, the complainant shall immediately prepare a statement in accordance with the approved reparation statement in Exhibit No. 1 to this subpart, showing details of the shipments on which reparation is claimed. This statement shall not include any shipments not covered by the findings of the Commission. Complainant shall forward the statement, together with the paid freight bills on the shipments, or true copies thereof, to the respondent or other person who collected the charges for checking and certification as to accuracy. Statements so prepared and certified shall be filed with the Commission for consideration in determining the amount of reparation due. Disputes concerning the accuracy of amounts may be assigned for conference by the Commission, or in its discretion referred for further hearing. [Rule 252.]