Young Players: How many games and what age?

[Enos]

I'm trying to use onl academy players in my current save and I'm running into some challenges.  Some of my players are completely ready for 15-20 starts and subsitute appearances 1st team football a season and I mix them in where I feel like they can succeed.  Usually this works out well, but I have 30-4 players who all have very high potential according to my coaches, but I'm not seeing any attribute improvement despite them getting 15-20 games.  Three players in particular are 18-19 and get decent ratings.  Usually I see significant improvement in their attributes as they play.  These three have been flat.  Are they late bloomers?  Are my coaches who have 17 and 18 JPP ratings off base?

 

I should say I defalut to double training for all of my 21U players.  These three I've taken them off double and put on normal for now, but that hasn't had an impact either.

Edited April 29, 2020 by Enos