In Central Region, yes, you can go back to package. The kicker is this: There has to be opening in package. You just can't bump back in whenever you feel like it and take your seniority with you. If there is an opening, then, yes, you can take your seniority and run with it. But, again, here anyway, you can't just bump into a package route. You either take what's left over or bid on what was opened or any new bids that come up.
Another kicker is this: Once you have gained seniority in feeders, bid run or not, you have to stay at least 3 yrs. It looks like this guy has fulfilled this part, being there 6 yrs.
Another kicker is this: As was stated in another post, you have to requalify in package. May or may not be easy. We had one driver that tried it. He was gone for 3 yrs, opening popped up in package, he made his intentions known, tried to requalify, didn't. Forced back to feeders.