Hi
If you map any macro knob to chain select ,chain select will miss a step and jump from 62 - 64 bypassing 63 and the knob then shows the wrong value,ie: knob and chain both show 0 at 0 but when the knob says 63 the chain says 64 because the chain skiped a step.
Also mentioned here a long time ago!
http://www.ableton.com/forum/viewtopic.php?t=50288