Great to finally have authoritative info on this!
I just have to say that it is arcane rules like this that are part of the reason why AA's CASM is so much higher than "sane" airlines like JetBlue and Southwest. You practically need a Ph.D. in linguistics and geography to understand those rules. I can only imagine the amount of time spent by agents, supervisors (when the agent can't parse the rule or the customer believes the agent is misinterpreting it), inter-airline liasons, etc. etc. handling this kind of stuff.
Once AA finishes cutting all of the food, legroom, routes, etc. that they can, hopefully they will take a look at the cost of operating the infrastructure that gives us arcane ticketing rules. I know that the theory is that such rules decrease costs and/or increase revenue, but I simply cannot believe that the analysis that presumably showed a benefit to such rules fully took into account the costs of supporting them on an ongoing basis.