There is also some to be said about how you operate the powder measure. I have had some say handle up (this is where it fills) bump the knocker to make sure the cavity is full then handle down to dump.
I prefer to go handle up, wait half a second for the cavity to fill then handle down to dump, then hit the tapper to make sure it all dumped. And when the measure is half full, full it up again. It seems to make a bit of diff how much powder is in the measure. IOW it will dump a bit less as the powder drops in the measure.
Any way I am happy with whatever the measure drops, I am not one to weigh each charge.
Oh, if you change to a new container of powder, always check weights as I have found the powder may vary a bit from batch to batch even with the same type and name on it.
Sorry, this thread was about labeling and ends up about powder measures. Hmmm guess we need to stick to the subject?
Anyway: Date, Bullet type and weight, Powder type and weight, Primer type and brand, are what need to be put on the label.