So, I just got FW 5.9 on my car and finally Smart Charging works. In the Netherlands such setups are very common. A house might have a 3x25A main connection and the Model S has to charge on that connection. The problem is, that when the car is charging and you turn on a stove or other heavy electric appliance, you might go over the 25A and blow the main fuse. For this Smart Charging exists. Both Smart EVSE and Open EVSE support this. The bug with Model S was, if the charging station said to the car: "Go down to 8A", it would go down. If the EVSE then said: "Go up to 20A", it would stay on 8A. This now works. I just verified it by setting the current back to 20A from 30A. That worked, Model S responded within 5 seconds. Then I set the max current to 24A and that worked as well. Within 10 seconds it was charging at full capacity.