Xpantastic!

I had posted some time ago on here about uneven resonances on my xpander-bizarrely, it corrected itself when I re-mounted the unit on my stand and the resonances are perfectly in tune.  

However, I noticed when cranking up the FM last night that despite my best efforts to untune and then retune, I could not get the FM consistent across the voices.  They are not wildly different, but different enough to make chromatic playing difficult.  

There is no consistency between which voices are more in tune with each other either, so I can't immediately say it's chip related.

So I guess my question is-should I expect the voices to be identical when full FM (on filter) is used?  I seem to recall this being possible when I first got my unit, but I don't actually use FM that often.