oh and I tried to find the link for it but when I was reading stories about BFL (which I plan on starting soon as I get my weight bench in the next few weeks) there was a sucess story this lady was 150 somthing lbs and a dress size 2 you'd have never guesed her weight she probably had like a 12% BF (judging by the definition to her muscles)
so maybe 180 isn't so unreasonable for a 6 or so you never know til you try