you indeed have a 5 speed 722.6.
722.3, 722.4 speaking, the switch flipped to W forces the car top start on 2nd gear and limits the torque, i am not 100% what it does on the top end.
722.5 doesnt have the switch, and starts on 2nd anyways unless you floor it.
722.6 i dont have the technical manual

i need someone to confirm that W position on 722.6 limits the max rev speed