I'm facing an issue with purchase orders in Odoo. My supplier only sells chairs in sets of 2. So, when I add a chair with the correct SKU and a quantity of 1 to my purchase order, I actually receive 2 chairs. Likewise, if I set the quantity to 2, I receive 4 chairs.

However, when I receive the chairs, Odoo only registers 1 chair in stock (instead of 2) in the first case, and 2 chairs (instead of 4) in the second case.

I can't use lot tracking because it's not supported for rental products (Validation Error: "Tracking by lots isn't supported for rental products. You should rather change the tracking mode to unique serial numbers").

How can I manage this situation where I order 1 product but actually receive 2 in stock?