I researched the 410c schematic as suggested by tbr. I can measure the input voltage at J1 and measure the input current as a voltage across the .1Ohm resistor r77 or pads 1 and 2 of j10 (both on the bottom side of the board).

    Idle, text  15.2v   115mA  1.75W
    Idle, X     15.2v   124mA  1.89W
    1CPU, X     15.2v  ~180mA  2.74W
    2CPU, X     15.2v  ~240mA  3.65W
    4CPU, X     15.2v  ~260mA  3.95W

All of my CPU loading scenarios had much more variable current readings, I tried to record the highest value I saw on a multimeter with a ~.5s update time over 10+ seconds.