The info I have shows they basically alternated between Bullseye No. 2 and Pistol Powder No. 5 from 1926 through 1941. Unless it is a misprint, they used PP No. 6 for Lot 499 in 1932.
Whether they alternated by intent or or that was how the bids went, I don't know, but I would not be surprised to learn that the Army tried to keep both suppliers happy by alternating purchases.
There is a disparity, though. The text says that WWI and postwar production was loaded with Bullseye No, 2 or Pistol Powder No. 3, both of which would allow double or even triple charges. Pistol Powder No. 5 was developed to more nearly fill the powder space and prevent overcharges and that it was "used intermittently until 1936, after which is saw continuous usage."
But there was one exception if the table is correct; it shows Bullseye No. 2 used in 1939 in Lot 676.
One point on lots. Even though they might have used, say, Bullseye No.2 for a couple of years, they still might have changed lot numbers due to a powder change. The powder used would obviously not be canister grade. So each powder shipment would probably have a new manufacturer's lot number; they would have had the lab test the powder and re-set the loading machines as necessary. And that would have meant a new FA lot number.
Jim