Lets say he grows into being a 25m player. I think that's his ceiling at Ajax.
That gives us about 12m back, so in total we might make about 17m for him.
It would depend on what the buyback clause is, if its anything around 10m, this is a good enough deal for us. Both parties are not losing money in this, while having less to profit from.
Now if he flops, we made 5m, which is what we would have made it anyways, while Ajax didnt overpay.
And this should be the model for Masia & Academy graduates going ahead.