(a) Any exemption granted under this part for an affected model year does not apply to a manufacturer that is ineligible under §525.5 for an exemption in that model year.

(b) The administrator may initiate rulemaking either on his own motion or on petition by an interested person to terminate an exemption granted under this part or to amend an alternative average fuel economy standard established under this part.

(c) Any interested persons may petition the Administrator to terminate an exemption granted under this part or to amend an alternative average fuel economy standard established under this part.