Hello Declan Walker,

your mathematical approach is great.
Three things :

a) I believe that the morale is a factor too in training.
b) I have trained a player on practice match 4 times in a row. As he was getting tired, his training progress was reduced each time. So I believe that his condition plays a role too in your calculations.
c) Having said the above, I believe that the numbers you talk about (20% decrease for 1year and 10% increase for a level) can be sometimes misleading and give you wrong results. Unless you came up with those numbers looking into players progress for many seasons.

Overall, its a very interesting and usefull approach