When I started turning necks I would turn each one individually. If it took more cutting to make one case's neck even I would cut more. I didn't just set the turner to take 75% of the material off of most necks. It took a while and the thicknesses aren't the same for each case, but I haven't had any problems. Now...whether it helped with accuracy, I couldn't tell. Will I do it with my next batch of brass??....not sure yet.