.02 gr won't make a difference. .2 gr might. My little experiment above shows that the RCBS scale will drift and will show that you have 46.0 gr but when weighed on a better scale the 46.0 is really anywhere from .08 to .2 gr heavier.
When reloading for long range shooting I like to take out as many variables as I can (or that I can stand to take out) I don't batch my cases by volume, only by case weight. I have 2400 Lapua cases, so batching by volume would be a career. I guess the other thing is that I have the tools (scale) to weigh charges this close, so why not? It it the same reason I use Redding dies and competition seater dies. No reason I couldn't use LEE dies but I find the Redding dies make more concentric ammo.
Maybe one of the most important things about this whole exercise is that mentally, my ammo it better than yours. Not saying it is, but in my mind it is. It's all part of the mental preparation of shooting, knowing that you have done everything you can to make the best ammo for the match.