I've wasted a lot of time recently looking at geometry charts and I'm a bit puzzled about something. I know that effective TT length is normally measured horizontally from the centre of the headtube to the centre of the seatpost. However, some manufacturers appear to quote an actual horizontal top tube length (centre of HT to centre of actual ST, measured horizontally), like Colnago with their EPS here:

http://www.colnago.com/bikes/2011/EPS

Is this just sloppy explanation on Colnago's part? Or if they are quoting horizontal TT rather than effective TT, how is one supposed to use the information?