I apologize for my late reply- I somehow missed this post.  I do currently have the unit sourced to BASS (tried GUITAR as well).  I've experimented with the delay, although it makes no difference to the tracking- the delay comes after the pitch shift occurs though, so I'm not sure why it would.   While the POGs may have processing that works in the way you describe, it would still be expected that the Pitchfactor, being a much more advanced unit, could at least keep up with them as far as tracking polyphonic 5ths and octaves, which unfortunately it can't.  Another example are the old Boss pitch shifters.  I use an old Boss VF-1 rack effect- it's antiquated at this point, but it's still a fantastic unit IMO.  It has a couple pitch shifting algos in it, and you can alter the input delay to allow for better tracking.  I can input any interval/chord and pitch shift it to any scale degree and it will play without warbling.  There's obviously a small bit of delay, and the tone doesn't sound as natural as the Pitchfactor, but it works very well, and I'd really like to see polyphonic tracking at least as good as this on  the PF (I can record comparative samples of both units if you'd like).