Look at it this way:
Is it worth risking the seat post snapping? Sure, because you will have to buy a different post regardless.
Is it worth getting injured when it snaps? Sure, you just call it a rebuilding year.
Is it worth potentially breaking your new Roubaix frame? No, it is not. After the deliberation and story that went in to it, it is MasterCard priceless at this point.

The minimum insertion reduces the load on both the post and the frame, so I wouldn't cheese it.