Board Thread:General Discussion/@comment-33353230-20171024183821/@comment-33728484-20171024185911

Only TURs (dokkan awakened URs with a max level of 120) can be reversed. And because Buffed Buu is just an SR, he doesn't even have a potential system, so it wouldn't work either way.

If you want to open up a path you have to dokkan awaken the dupe, although keep in mind that the reason why he was so common on that banner is because Slugghish Kid Buu can be used to raise Kid Buu's SA (if you're interested in that).