>>55732752Not sure what you are getting at. OP is talking about training a lower level mon. Nothing was mentioned about over leveling. And on most games I keep a few bench mons and switch them every so often to spread the XP. You should try it if you have over leveling problems.
>>55732762Just weaker or vastly lower level? If just weak because lacking moves/evo, make them fight anyway if they have a chance. Just using your carry mons is boring. And if they are low level (Aerodactyl for instance late game in Kanto), always have them lead and turn off set mode temporarily. It really doesn't take long for one low lvl mon to catch up to an adequate lvl. Then turn set mode back on when the mon in question can start to handle fights but itself, even if it's still a bit lower than the rest of your party. Just try to use it more.