So let's say I got a case like this with the FIFO costing method:

1. I ordered 5 chairs from vendor ABC for $100 with PO reference PO001
2. The next day, I ordered 8 chairs from vendor XYZ for $80 with PO reference PO002
3. There are 2 chairs from PO002 that is not in a good condition so I returned them to vendor XYZ

Based on point 3, why is Odoo using the cost from the first purchase for the journal and inventory valuation even though I'm returning the second purchase?

Is FIFO also applied to the product return scheme too? Because I think it should be applied to sales only or maybe I'm mistaken? wdyt?

Could anyone help me? This thing really bothers my mind haha

Thanks before for the answer and insight :D