I've never used the on-line tool but people use it because it seems to get a ticket issued at the originating-city price despite where the purchaser lives/is at the moment/has his credit card from. Calling AA RTW desk at DFW will get the USA price unless you can talk them into queuing the ticket to their South Africa agency, which some post suggest may take some persuasion.

I'm surprised at the report that the SA office didn't want to deal with you. I booked with them perhaps 6 weeks ago and it couldn't have been easier. The agent who picked up the phone was as ready for my "AONE4 booking, please" request as the DFW desk and was at least as competent and customer-friendly as some of the better people at DFW. And as I noted, went ahead and did the fare calculation when the rate desk wasn't fast enough.

I had done my homework, knew my flights, had verified availability, and booked a simple 4-segment trip with him (worrying about that price rise). To me knowing I was "wasting" $125 was worth the slick and almost instant ticket-in-hand. (It did take a couple of days, waiting for the rate desk.)

Regarding code-shares, ITA will not offer the AA code-share if you ask for JNB-LHR. It will if you route JNB-LHR-LAX with or without a stop in London. And I believe that is indeed the deal AA and BA have in that region. The code-share saves a couple hundred bucks, the difference between BA's YQ and AA's YR.