I didn’t get a response from the vex community, so can you clarify this?
RobotC said they just report your Cortex value. Do you have some circuit compensation in series with the A/D port?
I just talked to Corey… he gave me the explanation. The 10k series resister is between the 470k pull up and the 20k pull down. Thus when a plug is inserted, it grounds one side of the 470k and the input side of the 10k so there is 0 volts going to the A/D. This finally makes sense.