Woodoworkery: Wake up man these things do happen
Yes they do but not the way you're saying they do. You're saying predetermined. That means no matter what setup you use the shot's going wherever it was predetermined it would. This makes no sense.
I think what you might be confusing here is the fact that as soon as you click-ding or otherwise-the result of the shot is mathematically determined and you have to wait for the rendering to see the result. That mathematical computation is where VEM and deviation come into play.