I used to work at a place that made smart chargers for EVs. They did all sorts of intelligent scheduling, V2H and V2G, grid response and load shedding, some really clever stuff. The standard for most charger interfaces allows for the vehicle to communicate a load of information to the charger, and almost none of them implemented any more than the bare minimum. I’m many cases the charger can’t even tell how full the car’s battery is, it just has to charge until the car disconnects itself and stops charging, and assume it’s done so because it’s full. So, I wouldn’t be surprised if Teslas don’t communicate as much over OBD as you’d expect given the standard it supposedly implements. Manufacturers seem to be quite content to keep that stuff proprietary wherever they can.