Elephant Man...It is not a stupid question. When your stroking arm is behind or ahead of perpendicular, at CB contact, it means that likely you are not striking the CB exactly where you think you are, or as accurately as you can. Yes it's true that some pros get away with things like this, but for the huge majority of us this small error will be magnified, especially as we increase the speed of our stroke. However, in the end, it is, as always, 'different strokes for different folks'! 
Scott Lee
www.poolknowledge.com
Scott Lee
www.poolknowledge.com
Maybe this is a stupid question but... Does the arm/elbow need to be at 90 degrees when Q to QB contact is made when breaking? I try to do this when shooting, but never paid attention while breaking. Be it good or bad I do not know, but you are past 90 degrees even in your warm up stroke. Still looks like a nice controlled break to me though.