I've just kept it simple and stuck with setting a start time to charge. I am fortunate to have 240v charging, so all charging can easily be completed during off-peak times if I set a start time. Unless you cannot complete your charge during off-peak, I would just set a start time and roll with that. Eg, I have a super off peak pricing from 11pm to 7am. I just set my charging to start at 11pm, and it will generally be completed within 1-2 hours. I don't have to fiddle with the peak settings, departure, etc. I also very much agree the charging interface is a mess. Why not just give a simple setting that allows you to set a charge window from "x" to "x". (11pm - 7am). The car could then figure out the best way to charge only using that window.