A perfect deterministic world simulator will imply the ability to see into the future, which would give rise to the "Dbz Paradox", even if that was not the point of the story.

It is not exactly a new revelation, if you include a model in the model, the problem potentially arise. What you typically do is to keep running the model with the previous answer, and hope the answer converge. It is a common technique for finding numeric solution to the more complex equation systems. I have done it many times. Of course, there is in general no guarantee that there is a solution, that the solution is unique, or that you will find it using this technique.