Or, is it only the number of positions trained that is significant (and not the number of players)?
So, how is better to do either train 4 (more I think is impossible) players on the position PF/C or only 2 at position C ?? Let's assume that players are quite similar.
Then, when you want to train only 2 players on that position it is getting less effective as you have to set it for 2 positions (PF/C).