For purchases through the AA RTW desk, one has always had to pay the higher price of the country of origin or the country of sale unless ticket is purchased in Canada and/or departure is from Canada. So anyone from the US (like the OP) can easily fly to Canada and purchase a CIR or ONE ticket for departure from any country. You can even call the AA RTW desk and have them set up the reservation for purchase in Canada before traveling to Canada to purchase the ticket. Frankly I like starting a RTW ticket from another country as it allows me to easily split up my travels into 3 trips and an added plus of a much lower price in some cases. Excerpt from CIR and ONE rules provided below:
When travel originates in a country for which a specific local currency fares is published and the ticket is sold
in another country, the fare will be that published for the country of origin converted to the currency of the
country of sale at the bank selling rate. The resultant fare must not be lower than from the country of sale.
Exception: Not applicable for sales made and/or travel originating in Canada or when BOTH travel originates
and sales are made within the European Common Aviation Area (ECAA)/Switzerland
TTBOMK, the online booking engine has always defaulted to the price for the country of origin.
I just did a search in the OW forum and found no post from the past 3 months contradicting that information. If you have a source for contrary information, please post it to enlighten the rest of us. TIA