Hi,
#define Z_PROBE_FEEDRATE_FAST 4 //Uncomment by removing "//" and change value
#define Z_PROBE_FEEDRATE_SLOW 2 //Uncomment by removing "//" and change value
And underneath "Horizon is the most accurate when homing feedrate is set between 1 to 4 mm/s."
Thus the above should be
#define Z_PROBE_FEEDRATE_FAST (4*60) //Uncomment by removing "//" and change value
#define Z_PROBE_FEEDRATE_SLOW (2*60) //Uncomment by removing "//" and change value
as Marlin measures those feedrates in mm/min. Of course I hope the mistake is in the numbers for Marlin and not in the the unit mentioned below, since 4 mm/min would be extremely slow. ;)
Cheers,
René