This does not seem like a subtle change at all:
"There’s a subtle change regarding penalties called on the defense during a pass completion, the penalty will now be marked off at the end of the entire play."
I'm assuming that does not mean you can tack a pass interference penalty onto a completed pass, but that's definitely what it sounds like they are saying. But that would be a big deal if you started tacking penalty yards on to the end of a play if it involved a completed pass.