Neck turning is also pointless unless you ream as well, otherwise you thin out from the outside but still have thickness on the inner neck. The error starts with a blank that is slightly thicker on one side and is drawn rather than formed over a patern so the error will draw with the forming process (as it is not extruded through a form) and flow forward until the case is discarded or seperated.
IF you wanted to be super anal you would clean, weigh, anneal, collet size or ream/Turn, then trim for every firing. This may explain why the Lee collet die was popular with stateside BR shooters as it did the inside and outside against a plug.