Steve- is correct in his clarification. The "number" the factory gives is a range. Just setting it to any value in the range, doesn't mean the car will react the way you want it to.
My local MB dealer alignment tech (he does 99% of all MB alignments at the dealer), does at least 2-test drives (freeway on-ramp right next to dealer) and hence two-setups to "tweak" the alignment just right. He even calls me for a final test drive including a freeway jaunt upto 75 MPH, to make sure I'm satisfied.
$90 for 2.5 hrs work, I'm very happy.