yeah jimmie explains his driving style, what really led to jimmie running worse was the reduction in horsepower. he explains his style uses a lot of brake, and a careful and controlled throttle off the corner. Last year with even the low downforce rules they were running a lot of throttle through the corners will very little off throttle. This years its blip the throttle slam the throttle all the way down. jimmie feels like his strong suit was on and off throttle driving. The NXS cars drove much like the way the cars do now with less power and more on throttle time. its likely why jimme was not good in the NXS cars and why he avoided driving them.
That is the explanation for most tracks. it doesn't explain why jimmie isn't better on short tracks where those tracks aren't effected so much by the new rules. Heck he doesn't even run well anymore at martinsville.
I also think HMS cars frankly have sucked, for whatever reason they aren't running that well. they get out run by gnassasi cars and even buescher sometimes. I think jimmie's problems are 2 fold. first crappy HMS cars. next a rules package that isn't his strong suit. if next year is jimmie's last, why not bring chad back for the last year?