Workflow

1. Create a purchase order for Azure interior, product: Meeting table, quantity 1 at $4500 unit price.

2. Create a ‘draft’ vendor bill in accounting for vendor:Azure interior and product:Meeting table. 
Quantity 1 and unit price $4600 due to inflation.

3. Create another line on the vendor bill called shipping. The unit price is $100
Now, there are no PO links to the vendor bill.

4. On the vendor bill, click on PO matching. Select the purchase order and the draft bill. This way Odoo links these two records.

5. Currently, the vendor bill has another line called: shipping while the purchase order doesn’t have a line item called: shipping.
To add ‘shipping’ to the PO to match the vendor bill, select the vendor bill line: shipping. Add to PO tab allows this vendor bill line item becomes a purchase order line.

6. Select the P00035. Add to PO appears as ‘down payment’ on the PO line