Use PROBE_ACCURACY for testing and reporting the repeatability range. The code I’m working on here is repeatable to about 2.5 microns over 50 probes, sometimes its less than 1 micron. An “acceptable” probe is less than 25 microns (0.025mm) of range over 10 probes.
Different speeds come with different amounts of noise. The noise is be both electrical and physical. The amount of noise at the load cell isn’t directly correlated with speed, just like stepper noise isn’t correlated with speed (i.e. faster can be quieter or lounder).
There is another thread, Load Cell Design, where we are discussing physical design of load-cell/toolhead integration. Would love to find out more about your toolhead and how it was built over there. We lack toolheads and sensor boards to enable people to test this code. Its a chicken and egg problem.