FxDrider got it. Next time you want to work on that file just open it within Quickload and tweak to your hearts content. Might want to save a copy though, Incase you want to revert back.
Like others mentioned, your measured case capacity in H2O (water) will also make the calculations that much more accurate. In my experience I’ve found that what QL predicts for muzzle velocity compared to shooting over a Labradar, is about 15 FPS from the calculated velocity. That’s close enough for me, I’m not going to mess with the burn rate of the powder.