I get exactly the same boil time too. Out of curiosity, does yours have the wirewool type burner? Mine does. I think this is an old design now, it's been upgraded a couple of times and I think the new design is much faster. I've seen 90 seconds for 500mls.
[video=youtube;b0QhKo5VgIs]http://www.youtube.com/watch?v=b0QhKo5VgIs&feature=player_embedded[/video]
