All of the SR that we have done have been overhead traction.. One was a 10 landing one was a 17. It was engineered with the IP8300 Selection system. however, the first selector was bad on the 10 landings and for about 2 weeks we were having position issues. replaced the selector and sent the other one back and it ran like a champ.. As far as floor levels go, it is my understanding that you have to adjust them in the up AND the down direction. I started at the top and adjusted and saved all the floor levels, then couldnt figure out why the heck they were off sometimes and not all the time.. it was when i was traveling up that they would be off because i had only adjusted in the down direction. SR tech support caught it while I was talking to them, I did them in the up dir. and no problems after that.