I think you came close to the answer. When IOWANS supported Huck, our jaws dropped. Now NH independents go for Romney and there are cries of "conspiracy!".
I think it's a simple matter of geography. New Hampshire Republicans (especially undecideds) would represent an entirely different political entity than other states. For instance, suppose Luntz had chosen GEORGIA Republicans to judge the debate. He may likely have gotten an entirely different response.
And from reading all the analyses, there's a general consensus that Romney did dominate the debates. I thought he won. So why should this group have been any different in their assessments? I was sorry they didn't like Fred, but have to admit they have a point. He just wasn't inspirational (and I've donated to him).
In fact I think that for New Hampshire, the focus group was probably pretty representative.
I am not a Fred fan, but I thought this was one of his better debates. He didn't hem and haw nearly as much as usual, and his answers were spot on.
And, then again, he may have extracted the same sort of response that he wanted extracted. You don't suppose that Frank Luntz's focus group operation has a steering committee, do you?