Hi, George,
You are correct, but I have seen too many mags that have lips almost as soft as the more kissable kind. You get the mag working and two (or less) fillups later, same old problem. The first step to fixing mag problems is not to have them in the first place. I may be extreme, but I use nothing for the .45 but WWII GI magazines, and use ammo that works in them, rather than adjusting the mag to the ammo.
Jim