The coolant temp only starts registering from about 80 on wards.
sometimes I have seen 3 degrees difference, but once the engine has warmed up, they sit on par with each other.
Please keep in mind that this is not an accurate reading. It could be wrong. there is no way to verify that the temp is correct.
I use to be able to plug in the laptop and use forscan to compare readings, however with the SCT4 and the locked tune, forscan does not work.