This is one area my installers messed up. Not only did they set the CFM wrong, they didn't enable Comfort-R.
Thanks to the Trane documentation and verification from this forum I was able to get everything set properly. I'm pretty sure you must jumper Y and O at the furnace or Comfort-R is not enabled.
As for the CFM, I made sure mine was set to match the tonnage of my system. I think messing with it is a bad idea; without enough air flow the coils could freeze.
The system needs to run for longer intervals to get the humidity out. If your system doesn't run long enough then it just might be oversized.