from what I have read it is 60hz (50 - 100%) and 240Hz from (0 to 49%) brightness.
Where did you see no PWM at 50% ?
This article incorrectly assumes there is no PWM at 50%.
https://blog.elcomsoft.com/2018/03/...to-stop-oled-flickering-in-just-three-clicks/
Technically the PWM is at its least steep curve at 50% brightness but still active.