The temp read with an obd reader does not necessarily mean the actual engine temp is incorrect. The temps sensor value gives a reading that the ecu converts, the thermostatic controlled value of the water temperature may well be different. In fact it almost certainly will by nature of the component tolerances.
I agree, it may well BE low, but it may also be ok. Only an accurate measurement of the water temp with a thermometer or infra red sensor will tell, or, test the thermostat in a pan of water.
ps, goodies arrived today Jon,

Spot on sir..
Cap. Joe.