I don't know where you get the information about S320's and 722.3, or 722.6, transmissions, etc, BUT I own both a 1994 S320, and a 1996 S320 (140.032). Both of them say the same thing on the build plate = the transmission is a 722.508 type. 5 speed, first gear start.
The parts program ( htt:\\epc.startekinfo.com\epc ) also says both cars take the same transmission.

I hope this helps with the confusion.

Comments, Questions, Corrections?

Farrell