I'm not familiar with all the turret presses out there but the only way I can imagine that a Lee press can fail to advance is if it's broken. Since each advance is performed manually by lowering the handle you are actually looking at the press as you perform the operation. If for some reason it were to stop advancing it would never complete the round anyway. Ball powders like w231, Universal, Titegroup and Longshot tend to be amazingly consistent never varying more than about a half a tenth either way. When using H110 though I find it is not consistent enough to not weigh each charge. But again, the very next steps finish that round. One issue I had years ago when using a single stage press was that it always seemed as though half way through filling up the loading block somebody would come to the door or dinner would be ready or some darn thing. An extra advantage to completely finishing one round at a time is that you can stop as soon as you finish that round (a couple of seconds) and walk away without having to worry later about where you left off. I suppose my original point was that it has to be a LOT SAFER to finish one round at a time completely.