I'll try again to explain how the tariff works using my schedule for tonight.
My battery is currently at 62% and I need to charge to 100% tonight for a trip.
View attachment 772615
Some points to note here:
1) IO has scheduled the charging over a total of 5.5 hours. Adding 38% in this time sounds reasonable.
2) The car charging scheduled is independent of the 23:30-05:30 off peak rates. You always get that period which you can use all through your house for washing, tumble drying, charging up other batteries etc.
3) Notice that IO has also scheduled a charge slot starting at 22:30-23:00. This will also be off-peak for the car charge and through the whole house.
(2) is good to know
(3) - does this mean effecitvely that there is only upside to the off-peak. In the occasions, perhaps not that often, that it chooses an earlier window then you're automatically shifting more load to off-peak so your overall house bill will go slightly down. So its an effective minimum 6 hour off peak, possibly more.