Customer order number on invoice from Sale Order

We use the Reference field on the Sale Order to record the customer purchase order number. As such, we are adding this field on the invoice.

I imagine we are not the only ones?

If so, would it make sense for this to be in the Tryton sale module?

I imagine this might be one of those things where the Reference may not be used for this purpose in some implementations and thus it might not make sense for this field to be surfaced on the invoice.

It already exists in standard module with the “Origins” field.

Yes, but not in the GUI.

The link is on each invoice line and there is a relate at the document level.