The relationship between bottles and case as you mention is 4 bottles = 1. case.

In this relationship, when 4 bottles are ordered 1 case was delivered, there are no bottles. Hence the return is only for case.

With your relationship a case can be directly sold.

If your product is ‘Wine with case’ then the KiT BoM components would need to be 4 bottles and 1 case.

This would create delivery of 4 bottles and 1 case, subsequently bottles and or case can returned.

Not sure if my understanding of your product to sell is accurate.

Hi,

Please refer to the module:

1. https://apps.odoo.com/apps/modules/18.0/sale_line_returned_qty_mrp

This module improves how returned quantities are computed on sales order lines when using Kit BOMs.

Hope it helps