Imagine it like this: Suppose you are a professional chef making chicago style deep dish pizza in cast iron skillets. You know how to make the recipe, and you know based on how you make each recipe how it is going to turn out differently. And you make each one the way that you intend for it to turn out. And it certainly does turn out that way. But that doesn’t mean also that it had to turn out that way, and the proof is that if I made the same pizza it would probably turn out differently.
So this situation is the same thing (assuming I made both).