What is the best way to enter items as received quickly so the quantities received can be changed easily after the fact for accuracy?

Often, when shipments arrives, they can take days, sometimes weeks to be counted, and it makes it difficult for employees to see whether an item has been received or not, particularly salespeople who would otherwise know they can take orders because by the time the order goes into production, it will be available. If the items were received based on the packing list, this system would reflect this receipt. However, for accuracy, we check the contents of every shipment to make sure it corresponds to what is on the packing list. 

The only solution I can think of is doing a return of goods. However, this is not a convenient way to make these sort of corrections, and I'm interested in whether there is a better way.