In concerns to another reason why centering a router bit in a table is very important. I am an avid Incra LS Positioner User. If that router bit is not centered it is a bear to set up that accessory to work correctly if you can do it at all. I create tons of boxes with up to four different registrations and I'll tell you if that bit is not in the center of the router table you get all kinds of interesting results. But once both the router bit is centered to the table and the Incra Positioner is centered to the bit life is good.