I wonder what assumptions were made in SYD about my fuel status after my G/A off 34R LOC after holding for 60 minutes for TRAFFIC . I bet they were wrong.
If it were marginal I wouldn't be concerned about their assumptions, I would be telling them the facts.
At the end of the day ATC don't know whats in our tanks, only we do, so if for some reason its getting doubtful, tell them and they will have to work things out.