Unless you are trying to hit a max load I would not worry about it. For a pistol cartridge you are not going to get a big difference in accuracy with a variation like you talked about. If you want to get good with a pistol practice your dry firing and shoot more everything else is not going to make a big difference. Some of the other posters are right, the choice of powder does seem to affect the consistency of the amount dropped from a powder measure. Good luck and happy shooting.