You mean Zatko is a significantly faster trainer than Rousar? Did you verfiy that? Take into consideration that Rousar is a 20 y.o compared to Zatko's 18.
I used only few greens for extra training of Rousar. Not significant but he is medium player.
Those players loose more after their 21 y.o. so consuming much more greens to keep them till 23-24.

The age for 18-21 y.o. firstborn players doesn't . Later they 're loosing value considering the next generation of ft.
All those years , with more teams besides my main and in lower levels where the max value is very obvious,
I have found 20 y.o. players with max value but few times bought them as their ft life is shorter.