Hardware
Hardware shop billing
Units, store rooms, and a rate for each party. POS at the counter. Sales tax on the invoice.
Units
A second unit when the same item sells by piece and by length.
Party rate
A trade buyer can have a rate of their own. The counter still uses POS.
Warehouses
Electrical, sanitary, tools, and paint can sit in more than one room.
Sales tax
The HS code can print with the tax on the invoice.