Third pary sales order- when is it closed

Iam testing third party process.

All the config is in place.

after i created the Po from third party sales order , i tried receiving the goods (statistical goods receipt) for it in diffeerent ways.

1) general MIGO for the Po quantity

2) Inbound delivery based on a shipping notification and then PGR from there (VL31N)

In either cases, the sales order workflow, does not get updates with the receipt quanity .

How do i consider it closed?

I checked a sap-img link

http://www.sap-img.com/sap-sd/process-flow-for-3rd-party-sales.htm

where they suggested to create a delivery VL31N after statistical goods receipt.

Not sure if that is a good way of doing business as it has lot of implications..as it is suggested for general deliveries going out of our company physically.

I would really appreciate how other companies work w.r.t receipts and closing of sales orders for third party orders

Thanks

AH