I just used the Competitive Cyclist fit calculator that they have on their website and they seem kind of large to me, I'm on my second road bike now, this one I built up from scratch starting with just the frame and think I have it down pretty good where I feel pretty comfortable on it. I've decided that I'm good on a bike with a top tube anywhere between 53.5cm and 54cm, any longer gives my neck and back pain. The fit calculator is suggesting a top tube of 55.6 - 56cm which seems way too large to me. The top tube is obviously the most important factor of bike sizing which I why I'm a little confused. The other measurements don't seem off as much but are still off by quite a bit. Any opinions?

Dave