I definitely understand what you’re proposing and I agree.
So, on customer side we have following workflow:
Sales Order → Sales Invoice(s) → Delivery Note(s)
or if goods are delivered before invoice, then:
Sales Order → Delivery Note(s) → Sales Invoice(s)
But in both instances the workflow starts with an order. So maybe when creating delivery notes or sales invoices, you could select which order is the invoice or delivery note related to. Then Manager could keep track of fulfillment status. One order could have multiple delivery notes or multiple sales invoices (if order needs to be broken down into multiple shipments or/and multiple invoices)
I’m leaving out sales quotes as they are really not part of the workflow. The workflow must start with an order.
Similar on purchasing side, you have a workflow:
Purchase Order → Goods Receipt(s) → Purchase Invoice(s)
The same concept.
Are we on the same page?