About grove electricity sensor and Wattmeter

Dear development team,
I am trying to use your electricity sensor to build a wattmeter. Right now, I am obtaining result which are pretty wrong (3 times what it should be).
I am using your formula:


power_consumption = (effective_value * EFFECTIVE_TENSION)/1000; //Calcul of effective power
Being in Japan, EFFECTIVE_TENSION should be 100 volts.
I have some question about your amplitude current formula. You use 5 volts in your calculation but in your sensor spec the sampling voltage is between 0 and 2 Volts. Is there an update mistake in your wiki? Did I misunderstand it?
Thanks in advance for your support,