Legends and ultimate legends

It seems like Ea always finds a way to beat us for no reason at all. How is it we can use ultimate legends to train players, but not the regular legends? And for the record, with all we have to spend and do to obtain certain players and train them we should be able to use any player for anything once they're on our bench, especially if we started training them. We can't auction them once we start training them which is understandable (but to be honest, it'll be nice if we could. Y'all always say y'all try to make it real as possible. We always lose progress and start fresh at the top of the season, a trained player in the auction is just like releasing a player to free agency.). But what reason is there why we can't even use them to train our other players? At this point in the season that's literally millions of points going to waste. A lot of times we can't even get a reason let alone an explanation from you guys on why things like this are the way they are. Why is it like this ea? Other people I've talked to and asked about this, and most other things, couldn't give me an answer because they didn't know. Is there a link or something explaining this?