I am trying to book a ticket from MEX - PHL. 8/7 - 8/21. I am in CDMX, Using google flights, even when I change the currency & location on Google Flights to US / $, I am seeing a price of $619. I click the link, it takes me to AA (MEXICO SITE), price is quoted in $ and pesos of $619. I go through everything but when it asks for credit card, it wants a Mexican based address. I'm given the option of changing country from MEXICO to US at this point, which I do, and everyting gets wiped out and takes me to AA US Site, where I have to start over and the price is now $672.

Anyway to book this ticket at the lower price? I'm confused and frustrated.
TRIED to upload screenshots of the Google Flights & AA site but I am restricted to do so on FlyerTalk because I haven't posted enough yet.

thanks.