Oh good point. Always test your learned codes in IR only mode without any sort of MRF unit involved. There are definately issues with IR sensitivity and the HR20, and even with the flasher against the side of the rack perpindicular to the sensor, it's still unreliable at times (favorite channel macros are the killer).

I actually had my most success when I had my MRF unit on the opposite side of the room pointing at my A/V rack, this seems to be most like just pointing the remote.