Follow the dolby spec and not some manufacturers manual.
Almost nobody has front and rear heights that is per spec.
My future home theater has only the rear atmos on the back wall being in spec. If I did the front wall. It will leave a major hole of sound above.
People just don't get the message to use angles from listening position to determine the speaker locations instead they blindly guessing.
To see evidence of why you almost never have front atmos on the wall see this image
To see front height and rear height that is in spec. See this second image.
https://ibb.co/kM7VQzd