The quote I am referring to is:
After finding this, I changed the code for AutoLeveller to store probed values in the parameters starting from #5161 so they could remain stored after a restart. Whilst it is true that these values are persisted, these values are system values and should not be written to. I have therefore changed it back to use parameters starting from #500 for storing the probed values. These values are not persisted but are 'user' variables, not 'system' variables, which are safe to use.The range of persistent parameters may change as development progresses. This range is currently 5161- 5390. It is defined in the _required_parameters array in file the src/emc/rs274ngc/interp_array.cc .
If you do want to persist probed values, you should add the values starting from 500 to the array quoted above (about 200 values should do it) but then this means editing the code which is not ideal.
Anyway, I just wanted to let you know the situation.