If my local supermarket is any indication those $/oz (or per 100ml in my case) are entered manually by employees and can be wildly inaccurate.
So maybe double-check them.
I used to work at Walmart. Maybe some stores print labels, but they are still disseminated from corporate and printed. They don’t have any control or ability to edit anything on the label
Edit for clarity: how we did it was some items had preprinted sheets that we could tear off from and others had printed labels we can stick on the shelf, either way the zebra handheld was connected to the corporate website, we scan the item with the price change, the printer spits out the new label and you place it over the old label. No editing or manually entering the price per ounce label, not sure of any store that does this by any means.. since accurate pricing is kinda the point of having a price per ounce label on the item..
I can kindof understand that. If the prices on the shelf don't match the register, walmart can get in deep trouble (at least where I am). Less to leave in the hands of employees where mistakes could happen. So in that case, the differences in unit types or mistakes in unit price is coming from corporate...
Sometimes I have to get out my calculator and do the division myself, but it almost always leads to a better shopping choice. Or at least confirmed my instinct