(a) When a complaint or a request for determination with respect to an airport fee or fees has been filed under this subpart and has not been dismissed, the Secretary will issue a determination as to whether the fee is reasonable within 120 days after the complaint or request is filed.

(b) When both a complaint and a request for determination have been filed with respect to the same airport fee or fees and have not been dismissed, the Secretary will issue a determination as to whether the fee is reasonable within 120 days after the complaint is filed.