When using the pick/pack/ship functions, the quantity on the scanner always defaults to 1 and the user has to manually push the button to change the quantity on the line to the actual picked quantity. This can become a very tedious when there are pages of shipping lines to be picked.
There should be a setting in the Sales Order Preferences->Warehouse Management tab that allows the pick screen to default to the quantity on the shipment line.
The purchase receipt screen has a similar option to set the default the receipt quantity to zero or to the PO order qty.