No, I havent taken the time to take myself off grid to check it. I was going to check it with my kill a watt type device but that requires me to take my house off grid to check, when my batteries are full. I dont consider the app "go off grid" to be a real test, so it means throwing my main breaker.
I kind of need to do this early on a weekend morning before my wife gets up and when we are not using much power. Since summer weather is here where I live (was close to 100 the past couple of days), not sure when I will do this now.