I recently had a situation that was practically the same. In the morning, I checked the result—everything was fine; by evening, the figure had already dropped, and after a couple of days, it started rising again. At first, I didn’t understand at all how this would affect the commission. Then I found an explanation from RoboForex and figured it out: the previous maximum result is taken into account, and the commission is charged on the new profit that exceeds it. That’s why the same profit isn’t counted twice. I’d recommend checking out the official example—it shows everything with numbers. Here’s the link; you can review it yourself:
https://roboforex.com/help/faq/copy-trading-traders/performance-fee-how-it-works/