ExpertFlyer Voice, thanks for replying and explaining. Weird that it is even possible to have more than one fare with the same fare basis in the same market -- I would have thought each market can only have one fare with a given name??!! What possible purpose to having two fares with the same name in the same market? Why would AA do that?

Can you suggest any workaround? Suppose I don't care which of these rules I read, on the view that maybe all the fares with the same name have the same (or substantially the same) rules. That might be wrong, of course, but it's a good place to start as I try to see whether these fares would work for me.