@saramg Legit concern, though: one of my cars is documented in gallons, and the other also in gallons, but one's imperial and one's us gallons. So the idea that there might be yet another weird local ounces, aside from troy and avoirdupois and fluid, is somewhat reasonable.
@smellsofbikes @saramg Yeah, this is a thing. Cars in Canada used to have better mileage ratings than US cars, not because they were more efficient, but because their gallons were bigger.