These price-per-weight things are sometimes inconsistent. Identical (save for flavour/chocolate-darkness/nuts-or-fruit-or-whatever-variations) packets can be listed as tens of pence per 100g on one type's shelf-sticker and exactly equivalent pounds (sterling) per kg on another. Easily converted between.
Cheese blocks, also, and price-per-100ml vs a price-per-litre 10 times higher on liquids in identical cans/bottles/tetrapacks.
Doesn't matter too much, mostly. At least it's not price-per-oz versus price-per-lb versus price-per-stone, or fl.oz/pints/gallons.
Though I
have spotted obvious errors, as well as mere conversion inconsistencies. A box of (frexample) six ?30?g cereal bars for a given price (the same for all flavoured variations) has been given price/120g (converted to
each of 100g or 1kg base units, seemingly at random) correctly, except for one sub-brand where the data-entryer has thinkoed and made the system display the (converted) price/
30g value, i.e. six times what it should be.
I even regularly mentioned one example of this to any nearby shelf-stacker/roaming-assistant/till-worker who looked open to a bit of smalltalk for several
months regarding the actual product I'm half remembering just above (I don't
religiously cross-compare my values for money, it just sometimes jumps out at me, and once I'd spotted this one I kept going back and checking it), and can only presume that there wasn't any simple way to pass on the information to the people sitting directly in front the stock-control computer. I
thought about taking the offending label off of the shelf, correcting it in red pen and shoving it in a suggestions/feedback box (each and every time it invariably got replaced), but I didn't want to be anal about it.