Quite honestly, I don't think everyone agrees on any of it, and I don't think they ever will. There are always those who will look at 1008.1, and say that the extra doors leading outside or to an exit are "doors provided for egress purposes in numbers greater than required by this code...", and therefore have to comply with all of the provisions of 1008.
In other words, there are those who will say that the door without the exit sign, but with panic hardware, is not a "required" egress door, but is "provided for egress in numbers greater than required in this code", and therefore can't be blocked. Egress means to go out. It doesn't mean required exit.
This issue has been debated many times, but there is never a concensus. I personally used to be in the "every door has to comply" camp, but am slowly moving away from that, and feel that panics (or panaics) should only be on required egress doors.