The ADC is 10 bit right?
So what is 1024, is it 3.3V?
I give it 1.48V and was expecting 459. But it is reading 472??
Does the SetLinearScale change the reference. So I can have better resolution
The analog circuitry on the board and in your circuit may not be cleanly separated, so that some noise is inevitable. You should try 0V and 3.3V to see what readings they give. You may also want to average several readings (filtering) to get a stable reading.