I tried this solution and it worked. Thank you.
I'm writing this as I've tested it, and it still works. Just launch the game beforehand and check whether the overwrite has occurred. The only thing that changes is the frame rate limit, which for some reason resets to the default when you launch the game. That's the reason for the change in the text file. Simply set it to OFF in the game, and the text file is overwritten with "0." That's the whole idea. Smoothness, responsiveness, fast gameplay. If you're writing this, it means that other technology is influencing these settings. I've never had this message before. So, don't write "WRONG" here. Figure out your setup, and I'm giving general recommendations. Everything works perfectly for me to this day, just as I configured it.
No, it doesn't reset if you leave read-only unticked.
There is however a bug in-game if you have a monitor with high refresh rate, where it shows 60Hz eventhough it's 400Hz(built-in refresh rate overlay confirms this). If I were to change any setting in-game, 400Hz wouldn't be available in full screen.
