User define thermistor: ADC value instead resistance

Hi Roland, there's way to insert in the on-line configurator the ADC value read with "M105 X0" command in the "User define thermistor table"?
I've the ability to physically detect the temperature on my nozzle with a precision instrument, and it would therefore be easier for me to be able to enter the temperature reading value and ADC instead of the resistance.
I think i've really wrong temp reading with my RAMPS V1.4 because the Arduino 5V voltage regulator go out only with 4.7V, so I guess this can cause errors in calculation of the temperature.
Bests,

Marco