Suppose I have a product A with stock quantity set equal to 10.

I create a sale order with ordered quantity=15 and shipping policy=Deliver each product when available. In this case I can validate the delivery order and create a back order of 5 quantities of product A.(2 deliveries in total)

Now with 10 quantity of product A in hand, next I create a sale order with ordered quantity=15 and shipping policy=Deliver at once. In this case also I can validate the delivery order and create a back order of 5 quantities of product A.(2 deliveries in total).

My question is what change does choosing the shipping policy have on the work flow. Can anyone demo with an example?

Thanks in advance.