Weight or volume?

Something's been troubling me. No, I'm not worried about losing my job, global warming, Iranian nuclear weapons, religious hatred, civil war or baldness. It's how malt was measured.

Brewing records (at least ones of the date I look at) all record the malts used in quarters. The quarter being a unit of volume. The weight of a quarter of malt depends on the type of malt, how it's been malted and a load of other factors. Generally, a quarter of pale malt weighed around 320 pounds, a quarter of brown or black malt 250-275 pounds.

The differing weights make calculations of the percentage of each malt in a grist a bit trickier, but still doable. Except there's another type of quarter. A weight rather than volume one. Which is 336 pounds for everything. Now here's the problem: how to work out which sort of quarters are meant. Are they working in weight or volume quarters?

First half of the 19th century, it's fair to assume a volume quarter. But later on? I'd assumed that after 1880 everyone worked in 336 pound quarters. But having this note in a Barclay Perkins Brown Stout log from 1921 has me confused. See what you think it means:

It's the bit in red: "Malts weighed at stated weights per quarter commencing this brew." What exactly does that mean?

See the "Weight per bushel" column? That's a dead handy feature of Barclay Perkins records. They give the weight of the malt. Multiply this number by 8 and you have the weight per quarter.

The way I understand that not, is that as of this brew, they were using volume quarters. Which seems like the opposite of what I would have expected. Or am I misunderstanding this completely.