I am aware of that, hence why I'm a little confused by my measurement. I bought and rode the original large (never measured it, but it had a "L" sticker) frame for a year and a half, and then this one for a few months, I'm fairly certain it's the same sized frame and I'm also fairly certain it's a large.

 Well I'm pretty sure it's the large frame so it should be 590mm according to pb, but when I put a measuring tape to it I got 565mm. It doesn't look short in the pic and I don't recall it feeling short when it was built up so I don't know why there's conflicting numbers, but as far as my measuring tape was concerned my frame has a 565mm top tube.