RAJBCPA:
After using my Dillon RL550B for over 25 years it has proven to me its ability to give duplicate drops of powder every time. Consequently, I set it then check it a couple of times in the first ten drops of powder then never check it again for an entire reloading session which is often a couple hundred rounds.
But..... I use mostly spherical powders or very small grain powders and only occasionally short cut extruded powders. Even then some powders don't meter well at all and for them I use a Redding BR-30 manually on an adapter on the powder die but that is only one or two calibers of my over 30 different calibers I reload for.
I will never suggest anyone else do it my way. If the book says check the powder drop every 10 rounds then that is what I will suggest. If and when you get confidence in the Dillon powder measure then you can do it any way you want.
As an aside, reloading experts (that is not me) from testing have found that exact measurement of powder to better than a couple of tenths of a grain are a waste of time.The uncontrolled variables in reloading swamp out any advantage of measuring powder to much closer than a couple of tenths of a grain either way from nominal.
LDBennett
I agree with everything said above except, IMO, you seem like a professional to me, or at least from my view point. Past that, ditto, ditto, ditto.
As for being off two-tenths either way? Heck, I could be off two tenths and the round is still going to be much more accurate then I am off hand. If I am progressing to the top of the recipe where I am maxing out my loads then I dial it in closer but past that, I don't worry about it.
My powder measures have no problem metering spherical powders almost dead on, and as for flake it is rarely more then one tenth off. I run several, check it, and if it is good I run it while keeping an eye on the powdered cases before seating the bullet. Then when my powder hopper is about 2/3 low, I refill, recheck, and I am off and running.