I have 30-yrs experience with this cartridge, 10 of which in national competition. I realize that my experience is irrelevant, so you just go your way! I only hope you don't hurt yourself or your firearm in the process.
I've seen a few 1911s turned into a paper bag full of broken parts by OVERCHARGES of fast powders like bullseye, but never from a light load, have you?
The only circumstance where it would be dangerous is if its loaded too light and the bullet doesn't exit the gun, then another is fired- I've seen this happen too, but not from an under charge, but from a cartridge that the reloader had failed to put any powder in. Them progressive reloaders are great tools, but they are only as good as the person operating them.