A standard way to approach these types of problems it to act as if you didn’t know whether you were the real you or the simulated you.

This may be a simplifying way of formulating the problem, but it's not an accurate description of what happens: there is no "simulated you", Omega only computes an answer to one question, your decision, about the counterfactual you. Omega's computation refers to the counterfactual truth about you. In the problem statement, the topic of discussion is the real you.