Update/Correction.

Still driving/loving the Honda in spite of the saleman. The dealership local has changed names and perhap owners. I got the oil changed and the software update done. The service department was very good.

I read the owner's manual and it turns out that "S" is for "Second".

From the owner's manual:

Second (S)-Selecting Second shifts the transmission into a lower range of ratios for better acceleration and increased engine braking. Use Second when you are going down a steep hill or in stop and go driving.

Low (L)-To shift to Low press the release button on the front of the shift lever. Use Low to get more power when climbing and for maximum engine braking...