Meanwhile, electronic price tags have been introduced in the market.
It's these small e-ink devices that are tethered to a central input station in the backroom, where a person inputs prices.
I've seen tags change in front of my eyes, updating price, adding promotional info or changing the product available on shelf.
Inventory movements are not an excuse, I'd say. Regardless the end sale price, if a product is not sold, it is just inventory, which value is fixed for the company.
Lidl moves tons of non perishable inventory from central wharehouses to stores, daily, and they could not care what the end price was at the store. A given item may cost an X amount in a given season, disappear for a couple of months, then return to the shelves with a different price. The inventory value does not oscilate.