Assessment agreements shall be filed with the Commission and become effective on filing. The Commission shall thereafter, upon complaint filed within 2 years of the date of the agreement, disapprove, cancel, or modify any such agreement, or charge or assessment pursuant thereto, that it finds, after notice and hearing, to be unjustly discriminatory or unfair as between carriers, shippers, or ports. The Commission shall issue its final decision in any such proceeding within 1 year of the date of filing of the complaint. To the extent that an assessment or charge is found in the proceeding to be unjustly discriminatory or unfair as between carriers, shippers, or ports, the Commission shall remedy the unjust discrimination or unfairness for the period of time between the filing of the complaint and the final decision by means of assessment adjustments. These adjustments shall be implemented by prospective credits or debits to future assessments or charges, except in the case of a complainant who has ceased activities subject to the assessment or charge, in which case reparation may be awarded. Except for this subsection and section
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(a) of this Appendix, this chapter does not apply to assessment agreements.