What you are describing is quite common, that is why I have more than one powder measure, for throwing into the case without weighing every charge I use my Harrell's. It is much more accurate with some powders than a Uniflo.
If neither of those two work to my satisfaction then I use the Chargemaster.
The curious thing to me is 4064 in a 270Win ????? can think of about 20 different powders I would try before I got to that combo.........