If I understand BA tier points correctly, you won't get any more points by going JFK-SYD (not a second transcon IIRC) than you would going LAX-SYD. Therefore if you saved your transcon to the end, like JFK- or MIA-LAX-SYD - wouldn't I be right that you'd get 360 tp for the journey compared to 180 for JFK-SYD?