SAP allows you to use Handling Unit functionality with and without the elaborate configuration required for managing Handling units. If you just want to use the Handling units without the storage location being marked as Handling Unit managed storage location you can do so. Both these cases could used depending upon the requirement .Primarily this is the difference between both the scenarios
Handling unit managed storage location:
1) Only packed material can be stored there; all stock must be packed .
2)Handling Unit requirement’ indicator has to be set for the storage location in customizing
3)A (non handling unit managed) partner storage location has to be assigned from the same plant.
4)When Handling Units are unpacked, not-packed stocks are posted to the partner storage location.
5)Handling Unit Management enables to control inventory management using packed stocks at storage location level.
The guarantee that the total of all Handling Unit stocks is the same as the stock in the storage location, is only valid for handling unit managed storage locations. This is because the incoming and outgoing material is with inbound or outbound deliveries respectively.Since the material is packed as per the qty specified in the delivery we know the total quantity in each Handling Unit in the storage location.
If you have Handling Unit on storage locations that are not HU managed, you never know if the stock in the HU physically exists and if the stock information is still valid. There is no guarantee that the data is correct. This is the biggest drawback of not making the Storage location HU managed.
In such a storage location we can pack and unpack goods into an HU with transaction HU02.There is no check in the system to control this. Which means physical integrity of the stock quantity with the system HU stock may be compromised.