Hello  Jon DeLee,

There are three kinds of power: Active power(P), Apparent pow er(S) ,Reactive power(Q)

Our meter only monitor Active power(P)

Apparent power: S= U*I

Active power : P=U*I*cosφ (cosφ is power factor)

Different load have different power factor,  so active power is not always equal to U*I.

For example, the cosφ for pure resistive load is near 1, so the Active power can be closed to U*I ;

The cosφ for inductive load and capacitive load is between 0-1, so the Active pow er is less than U*I.

Our meter also read power factor. You can check that.

And the reset button is under the lower right of meter, there is a hole, you can press it with wooden stick or other thing, just hold 5 seconds, then kwh will be reset.

Best regards,

DROK