I’m going to move your topic into the xTool section to get more interest and attention.
One user with a D1 1064 infrared felt that it was very sensitive to focal distance and that accuracy was lacking with the focal depth tool. This was proven out by the user by conducting a ramp test.
If you have a test or practice piece that is fairly flat, you set the focal distance further away from the work than expected, then with the work tilted, engrave your way toward the top of the ramp.