So, I opened up the Aircraft Performance Monitor (APM) to enter a new reading. I typed in the requested values from my sim (gross weight, flight level, cost index, TAT, TAS, ground speed, etc.) and eventually every box was filled. I put in the requested data, and PFPX calculated the remainder. Like I said, every field had a value in it, and nothing appeared to be in error (nothing was red, etc.). But the "Add" button at the top of the window was greyed out. Only the "Cancel" button worked. Are there any tricks to being able to add a new value? Thanks!
I did get some performance improvements by doing what was listed above, but the CRJ Pro is still pretty demanding in its current state. For now I have just been turning down some settings when I fly this aircraft. This should at least help with the FPS fluctuation problems.