So apparently Tim has instituted a O&A "pre-show" from 6-6:30. They also have a post-show from 10:30-11, but I don't think that's a new show.
The pre-show for a four-hour show seems a bit odd, especially when such talk shows are supposed to seem freeform. What's next, a "post-show preview at 9:45?"
Way to go, Tim!