Tools designed to center over the objective and barrel take some things for granted. They assume the center of the reticle is in the exact center of the bell, and that the barrel is perfectly straight and that the bore is also concentric to the OD. I have an annoying 2nd place plaque from a GP where I missed half of my 10-12y easy shots after relying on the Wheeler Engineering reticle alignment tool to set up my scope alignment. Lesson learned.
Like a broken clock...they can give to good info once in a while.
Mike