Need a little help understanding G31

[antlestxp]

I have just installed a PINDA v2 probe. The probe is configured and working properly as it should with the exception of the huge temperature drifts I am seeing with a warm bed. I have the thermister wired in and configure. I can monitor the temperature and I have the probe set to use it. Where I am lost is calibrating the temperature adjustments and what the G31 "C" and "S" command are used for. I am using RRF 3 on a maestro. I wouldn't worry about it if the drift was small but I see a trigger height difference over 1mm from a cold bed to a 90degree bed.

; Z-Probe
M308 S2 P"e1temp" Y"thermistor" T100000 B4725 C7.06e-8 A"Pinda" ; configure sensor 2 as thermistor on pin temp2
M558 P5 C"zprobe.in" H5 F160 T6500 B1 A4 S0.02 ; set Z probe type to modulated and the dive height + speeds

G31 P1000 X0 Y0 Z1.35 H2 ; set Z probe trigger value, offset and trigger height