I don't think casinos have different agreement with the gaming provider, what you said is happening behind the scenes. Although we may not say accurately how it happens or the way casino configure the gaming software in their favor. Because looking at the house edge the casino has control over the results we get from the games. While the gaming provider gives access to the game, does it mean the casino also has the right to change some commands on the software. That, I may not explain, but it's safe to say, yes. As the provider only offers a service and casino need to maximize profits. Other thing that confuses me is the provably fair feature, the casino guarantees players that nobody interferes with the outcome of the game. Hence, it's another view of idea, which means the casino could contact the gaming provider to configure the games in their favor, while the casino wouldn't bother changing a thing in the software to keep to their provably fair promise.