it’s always in the same units because the labels are printed by the same grocery store
That’s not always the case, which is the frustrating thing. I’ll try to remember to take photos the next time I go shopping, but for example at my local Costco some bulk packs of drink cans and bottles have a unit price per can or bottle, while others have a price per fluid ounce or per gallon. At my local Walmart, there’s some items priced per pound directly next to items priced per ounce. Similar product, just a different brand.