That was my understanding too – the other variable is ohme – I have noticed they appear to have the ability to charge at a lower rate – after I had made my post I noticed the app at one point was saying charging at 4 not 7 – maybe I just happened to select a time that hit the sweet spot – that’s how it works – so I plugged in about 2pm and said be ready by 9 am – the choices then as to how and when are left to ohme – hence the cheaper rate.
So maybe just coincidence – I am on a 250 mile round trip on Sunday – so will be charging back up late Sunday afternoon for 10 am Monday – so will pay more attention this time .