It helps to know what your voltage is at the outlet. While my P300 defaults to 117v and in the past it was common to describe our voltages as 110v,220v, and 440v [3 phase]. I have found my usual voltage measured at the various outlets with a digital multimeter to be 126v. So I set my P300 to 120v, as I know it has a high enough incoming voltage, that it doesn’t have to work very hard to maintain 120v.
I know the P10 is more advanced than the P300 providing much more information. Mine shows me in watts how much my equipment is using. Does the P10 show how many amps it is pulling?