Hi I am new to this game and read some posts on stars and power train.

Question:
Say I have a 6 star player. If I am promoted to next league the player will become a 5* player. Will the gain from training improve back to what he used to register when he was a 5* player? For discussion please ignore age factor.

Since the gain from power train reduce significantly once the player is levelled up to 6*, what is the use of power training a player over 6*? Wouldn't it be better to save the rest and PT at the beginning of next season, when he is bk to 5*? For discussion assuming my team has a comfortable lead over the rest of the team this season.