I must say that I agree with Axel. For me, there’s no such concept as the right quantity of a sale line.
When I want to analyze quantities sold I must decide what information I want which is at least:
- Quantity Requested: the one that sales manage
- Quantity Shipped: the one that shipments / stock moves manage
- Quantity Invoiced: the ones in invoices
Of course, in all cases I must know what we’re looking for (typically the state of the document – or even the states in which it has been):
- If we want the quantity requested we can be interested in quotations only, quantities actually ordered, etc
- For shipped quantities, we may be interested in quantities yet to be delivered or only the shipped ones
- For invoiced quantities, something similar those that will be invoiced, those actually posted, etc
So when customers ask us to provide an report with their sales, we first ask the to clarify what “Sales” means to the in the context of that specific report. In most cases it is posted invoices, but not always. Invoices have the advantage that usually better match accounting information.
For me, trying to bring that information to the sale is a mistake but of course, it depends on what you’re trying to analyze.