Well, 1-2 pops a season, across 6 seasons of training, ends up being ~9 pops overall. That puts him about a season ahead, which is a pretty big deal for hall of fame potential. You can easily use a level 4 or 5 if you're training perennial allstar or superstar, as you can just train them for a little while longer to make up the difference. But when this guy would get to that level, he would be too old to train well.
You also have to take his age into it, as he get older training slows down, so if he get's 1 extra pop when he is 18, he might only get 1/2 pop at 23 or so.
I was just trying to point out that it only 1-2 pop's, just in case he is expecting 5+ pop's a season and he will be disappointed when that does not happen.