Do you have an example for that? As far as I'm concerned, you're right that a few newer songs seem to already been recorded a half step "down", meaning the guitar is tuned differently, probably and most likely due to Jon's vocal limitations. But still, all songs I've ever heard are tuned down one half step from the studio version, each and every one of them (not counting the rare occasion where the band performed one of the singles in the studio key, probably due to only singing live and having the band pre-recorded).