Chevrolet is not a
Chevrolet is not a Corporation. GM is, and therefore you need to include Cadillac and Buick into that equation. You might also note that it is against the law to PLAN to simply pay the CAFE fine on the premise that it is against the law to conspire to break it. So you'll not ever see automotive execs admit to this; they'll just say "oops, we never saw that coming".