A sale order comes to Order to upsell only if one creates the invoice according
to the ordered quantity and the delivered quantity is greater than the invoiced
quantity.
If we go through particular product details, in the invoice tab of that product
we can see an option called Invoicing policy. There we can see two options: ‘Ordered
quantity’ and ‘Delivered quantity’. If we choose the Ordered quantity, one can create
the invoice according to the ordered quantity of that product and if choose Delivered
quantity the invoice will create according to the delivered quantity.