The ohmmeter gives inaccurate readings on the board because some current goes wandering off to places unknown. There is the same problem with measuring voltage.
The reason i ask the question is that I would prefer to test resistors whilst still on the board using the voltages rather than across the resistor using an ohmmeter as that can give inaccurate readings.
that isn't going to be any more accurate than the other way
The only real way to confirm a resistor value is to lift one end out of circuit before measuring it
