"I followed the instructions you described to test it out (after making sure I could no longer program a code into my C7), and had no problem
assigning an advanced code to a non-shifted button, after clearing out the key with the shifted EFC."

Cool! Well that settles that issue...

I've got to try that "advanced code" of one device to another sequence again. Yes, I actually did try that one :) I'll update the FAQ if I can't do it.