All my HS110 plugs are connected to 240V power. This has been verified by a multimeter. As well, I did the wiring, breaker installs, etc myself ;) But the application is reporting ~170v. The HS100 plugs, connected to 120v are reporting around 86v. Which is interesting as the Android app doesn't present voltage at all. Perhaps it is not show in the Android app because the voltage is broken in the devices. And perhaps this problem is totally unrelated to your project. Because watts = volts * amps, this is all easy to validate that something is wrong. For example, one of my HS110 shows: 760w, 3.15a, 172v. The math doesn't quite work out here. And indeed, 760/3.15=241. So I trust the amps and watts, but the volts is wack.

  @JodaJacksoncatr 

Volts are correct on my side (230V - Germany). Watts are completely wrong (as you can see)