Pretty sure the ex-IST price has increased substantially; even if it has not, fuel surcharges have probably increased by more than USD 125 for the routing. Best bet is to change the ticket at AA after you reach the US. Changing before the first flight is not a change, it is refunding your original ticket and buying a new one from scratch (might cost the same, but it often costs more, plus you get new fare rules if they happen to have changed -- and those never change for the better).