Amount vs packaging amount

I'm not sure if the Summary field has the right wording but I understand it has to do with packaing quantity vs quantity of the goods.
 
Line item quantity/unit. There is no appropriate place to put this in the DBC UBL. UBL 2.1 supports a Dimension element “A class to define a measurable dimension (length, mass, weight, volume, or area) of an item.” but I’m not convinced this is what the “Unit” column actually represents in the Holco invoice. All elements which mention Backorder/Oversupply/etc correspond to DespatchAdvice as opposed to an Invoice in the UBL model so it feels like this is blurring the lines between an order/invoice/despatch advice. I’m inclined to argue we should put this information into the InvoiceLine/Note field (similar to above at the invoice level) and then provide feedback to the DBC to see what they suggest.