Alan,
I'm having a horrible time with CM with the z3100 since the firmware/driver upgrade to 5.0.0.4. I firmly believe that I am getting profiling done by the printer even though I've selected "application managed colours" in the driver. I've checked driver / application / windows settings dozens of times and made dozens of check prints, and never has the colour been closer to "right" as to when source data is passed to the driver as unmanaged sRGB and I let the printer do all CM.
This flies in the face of everything I've learned and used on every other printer, and even with this printer when I first started using it.
At this point, I am so frustrated with my inability to get a clean application managed colour workflow, that I have just printed a target with printer CM enabled so that I can try a workflow with intentional double-profiling (app & printer) -- with the hope that colour will be at least consistently applied.
I've wasted several pounds of paper going around and around with this and it's really driving me crazy. I have portraits to produce and skin tones must be perfect!
N.B. this happens whether I profile with the printer's built in software/hardware or use standalone x-rite software/hardware.
-s