SOC Kaput or Operator Error?

The SOC on my 2009 eS has been displaying all green bars for some time. After replacing my batteries (AGM with AGM), charging them and running them down until the car “turtled”, I reset the SOC (press,up,down,center,release,etc.) to 0 and it displayed one red bar.

I charged the batteries overnight and the charger indicates a full charge. But the SOC is still only showing one red bar.

I went for a drive and the car has full power. All the other lights on the dashboard are bright and functioning as designed.

Perusing the site, I find that “function 15 needs to be set at 72” but no instructions on how to check or change. I find nothing in the owner’s manual.

Can anyone recommend a fix for this? Any input is much appreciated.

D