Grove GSR sensor v1.2 formula + calibration

Hello! I have some questions to GSR 1.2v sensor.
1)What is the physical origin of the formula used? Why is the resistivity calculated in this way? What means multiplying by 10000?

Human Resistance = ((1024+2Serial_Port_Reading) 10000)/(512-Serial_Port_Reading), unit is ohm, Serial_Port_Reading is the value display on Serial Port(between 0~1023)

2)Following this formula I get the following results (viz foto). They make no sense, because based on the formula the resistance should be in ohms, and typical human skin resistance values are 2 kilo to 2 mega ohms. The results from the sensor are 1000 times less than the reference.

Thank you!

Before wearing the electrodes, you have to use the screw driver to adjust resistor until the serial output as 512. Did you perform this step?

Of course, but the main question and problem is why formula looks like it is. What does mean *10000, why 10000 and not maybe 500.