Simulators are garbage, so you can't really trust what they say. I'll tell you how I would personally figure the amount your score could go up though:
Your FICO score can range 550 points (300 to 850). Of those 550 points, 30% of them go toward utilization. 30% of 550 is 165 points. It's then possible to consider that going from the "best" possible utilization (1%) to the "worst" possible utilization (maxed out) could result in a score change up to that amount. We are talking FICO scores here, not Vantage scores which CK provides.
So if you have maxed out utilization and your FICO score is 550 and you take your utilization down to 1%, you could potentially see a score increase up to 715. In order to see that amount though everything would have to be perfect, meaning you'd need at least 3 total revolvers with 2 out of 3 reporting $0 balances and the 3rd one reporting a small balance, say $10 (but up to 8% of the limit would be acceptable).
Hopefully that helps a bit with your ability to estimate.
