Well, I 'm only sure for the levels I 've been so far. This season I 'm lv7.
I bought this player (a nordgen one) because he was one from the most expensive in this lv (although there are some higher prices like 18M').
He is a classic 5* good trainer. He started with +90 to +140 in 3 bars practice match and now that he is 6* 56q gets +65 to +90.
His Value from sp is now 18,7 M' from 15,3 M' while his wage stayed the same 500K. I can't renew his contract now but if I would like to do that in the new season, his wage would be in an analogy with his new Value. Suppose that I want to sell him. If someone buy him, the value and the wage will be the same (no matter if the value gonna raise from bidding).
If the new mgr have 22 players, sell one of them and after that sign with Gerson, he will pay him more than that 500K'.
All those above, has nothing to do with his train ability. The indicator of his train ability is VALUE15,3 and WAGE 500K' - the first time he started in the game. Now for the next of the season his raise will be dropping and in the new season, if he will be 5* again, he can have the same numbers as the beginning (-some % because of 1 year older).
* I changed his name to an old brazilian legend
** I don't buy 3*-4* players. This one Schmitt, probably is an academy player. In that case maybe I could compare his VALUE/WAGE with a nordgen 3-4* player of this lv as an indicator but academy players are unique category. Maybe can be super fast and maybe sometimes good-medium trainers.
*** usually I don't sign academy players - they are fast trainers but they lack of quality (for the Token I need to pay) so I need more time and packs to get them to scout lv if comparing with a 5* nordgen. They are 4* and they have those weird quality like 65-66