PLA rules are defined for an item classification at the UOM level. A PLA rule points to a list of zones. Multiple PLA rules may be specified to ensure unique zone level constraints for each combination of item classification or UOM. For example, for SKUs stocked in pallets, cases, and loose units, you can define 3 distinct rules to cover zones that are applicable for each UOM.
The identifies the PLA rule for a wave by identifying the appropriate pick processes starting from the biggest UOM defined for the item.
If the pick process determination rules are not defined for a UOM, and if other conditions are met, the pick processes can be selected using any UOM.