Lets see, a difference in TT length of 1.5 cm, thats oh, 0.6 inch. Get real. thats not a signifiant difference. How long of stem do you think is corect by the way? the difference between 80 cm and 100 cm is still less than an inch. I find more difference due to early/late season flexabilty and conditioning to make a greater difference than that. It probably more the overall geometry of the frame than anything about the fit.