Thanks for the reply and thanks for taking the time to find the video. He makes some interesting points. When he shows the seat on the Aeroad being the farthest back the numbers do not show that. For an XS frame the Aeroad has a top tube of 527 (the same as an Endurace?) and a reach of 376. An XS Utimate has a top tube of 529 and a reach of 378.
For what it is worth, unless I am measuring wrong, the bike I am riding has a top tube of 525 but a reach of 390?
I will ask this question in a separate thread so I don't clog this Canyon specific thread with all these geometry questions. Thanks again.