All of the above having been said, I've learned from this thread that the suite of editors that comprise CCP is not a suite of editors. "Suite" implies that it's a cohesive collection, and that they all work the same. It is instead a collection of editors of different abilities and properties. This has led to confusion in this discussion: we should have always specified which remote we were pretending to edit.

For instance, I mistakenly last looked at this problem with the MX900 editor. (I can't imagine why I had ever gone there!) Looking now at the MX990 editor, I see that when I go into Programming and IR Data, clicking on AV Receiver, the brand and a model appear. (With the MX-900, the brand did not appear at this point). And the first model in the list that uses the Setup Number is highlighted. And this is NOT the model number I chose.

Here's something that could make sense, though that's no proof that it happens: if, at this point, you know the Setup Number and you enter it, a set of commands appears in the Function window. The question is, is that actually the set of commands for that Setup Number? NOTHING is highlighted in the Model column for any kind of confirmation.

Thinking about this for a second, what would make sense when approaching the process this way, perhaps when you type in a Setup Number, all the Models that DON'T use this Setup Number should drop out of the list so you're only looking at the models that do use it. That is too much to ask, though.