I use a single stage loader for all of my reloading.
I'm not a competition shooter but, I demand that my guns shoot very accurately. What I've found out is the difference in .1 grain doesn't affect accuracy. There just isn't a difference in pressure between those loads that makes one hill of beans, if proper detail is shown on the other aspects. Same seated depth, same crimp pressure if one is applied, the "sweet spot" distance from bullet to lands is found in combination to crimp amount and seating depth, same primer lot, same brand of case, etc....
My Lee perfect powder dispenser will get the load within .1 every time. And. most times after running 20 or so charges through it, it will get it exactly right most every time. If not, it might be .1 lower or higher on large granulated powders. Something like 2400 and it is dead right every time. That is assuming the electronic reloading scale I check every 10 or so rounds on is not deviating. It is so precise and sensitive, most every load that does say .1 difference when testing, the powder pan can be removed and laid back on it in a different area and often, it says the exact charge that time.
So, it is a wash in my understanding, experience, and thoughts. I will say this, once you have the powder dispenser set to the charge you want, when going through the motions of loading the shell, do it with the understanding of what it takes. When raising the handle, let it set until you hear it fill with powder etc... It only takes a 1/2 second to get it right but, in my experience, when it shows .2 deviations in loads, it is due to going to quickly with the powder loading.
To sum it up, they are extremely accurate if used correctly. and using them will show zero detriment in accuracy versus hand weighing and filling each individual case. God Bless