I've shot thru going on my 4th jug of the 209 and I have all the jugs yet, as I keep loose nuts and screws in them in the shop. I just peeked and all have different lot numbers except the two most recent, which are #29. I've weighed my 209 charges from the get-go and currently shoot this powder thru three guns, soon to become 4. Two of these guns are smack on at 100 yards and less than moa. One is a 50 yard gun [Optima pistol] and is right at an inch at the 50. All are scoped. These three guns were sighted using the first jug of 209 powder using the weighed charges and getting no correction between the jugs they still shoot dead nuts. I honestly don't feel like there is enough or broad enough disparity between lots that accuracy is going to be a factor unless someone is using the 209 powder for very long range work. For hunting purposes the 209 just shines so my suggestion is to find a load [either weighed individually or by volume] that's accurate using all the components you intend to hunt with and focus on what can be done with that at the range. Decent cleaning, breech plug erosion and practice are larger factors to fret over and are usually more concerning that the weight vs volume on the powder.
It sounds as though Western has addressed the issue and has it dialed in now. I'm super happy with the product and have been even not knowing there was a difference in weight/volume. I'm darned happy with the accuracy I have been getting and I don't plan on worrying about the powder issue.