It’s a general note, not something especially to exclusive gambling.
I do not know the CPA you have but let’s say it’s 50$. So,if your players earn the casino less then 50$ on average, they most likely won’t pay you (yet).
If your players keep underperforming (= making the casino less money then they have to pay you), then they will switch you to revenue share anyway.
So, it is reasonable to understand that CPA can not be better than revenue share; if your players earn the casino 200$ or more (so your 25% commission would be 50$ or more on revenue share – players are ‘overperforming’), then the program will be glad to pay the CPA of 50$. However, if your players are aerning them less than 200$ (so your revenue share commission is less then 50$ – players are ‘underperforming’), then you will be transfered to revenue share soon.
PJ