In a total calculation, is it possible to include only the by-product, including a condition?
Suppose the main product costs €100 and the by-product costs €20. The total amount is then €120. However, to the by-product comes €2 packaging cost. How can I correctly reflect this in the total amount? If no by-product is chosen, the packaging costs should not be included in the total amount. Currently, however, these packaging costs are always added no matter what I try.
