You've never had one that was way off? I aligned a 19t last weekend and it was way off. The only way to align it was to shave a little material off the plates and enlarge the plate holes. Typical trinity stuff, the brush was wearing 3/4th of the way across the brush instead half way. I've never had a motor have perfect alignment without spending 30-45 minutes with some square brushes doing it myself.
I don't touch the endbell holes though since you can strip them out if your not careful.