Payments for liquor stores, from the case on the pallet to the single bottle at the counter

Because that is the only moment both numbers exist in the same place. A case arrives as one line on a distributor invoice and leaves the shelf as individual bottles, and if the conversion is not applied when the pallet is checked in, the count is wrong from that day onward. Fixing it later means a full physical count.

Yes, whenever you carry more than one at a time. They were bought at different costs, they sell at different rates, and the older one is usually the one you most need to watch moving. Held as a single item, cost of goods becomes an average of two purchases and the slow vintage hides behind the fast one until you are counting.

As a rule the register evaluates over the basket: a quantity, a category the bottles have to belong to, and a decision it makes on its own. Anything that requires the clerk to count bottles and remember which ones qualify will be applied inconsistently, and the inconsistency runs one way on quiet nights and the other way when it is busy.

A machine-read date, a refusal the system enforces, and a record that the check took place. On the nights this matters most the shop is full and the queue is long, which is exactly when a visual check degrades. The record is also the only part of the exchange that still exists the next day.

Because nobody consults a policy document at the moment an order is placed. Hours, areas and who may receive an order are set by the jurisdiction you operate in, and the ordering flow is the only place a rule can actually stop something from happening. Written down and not enforced, it is a rule you will find out you broke.