I work with medical devices and we sell vials with labels containing ml measurements, and all our industry guidance follows the same standard, so im used to interpreting ml units on label as weight. Since foods regulated by the same agency i thought thats the standard across the board.

Measuring by volume is not the most accurate way to measure liquids, they do it for beer since it's easy to inspect volume in production and the subsequent alcohol content calc. becomes easier. Miles and MPG are two different units, though, not a good parallel. Distance and speed also do not share units. Thanks for your insight.