@lukasz The only potential workaround is to use Lot Numbered Items. If you select "Lot Numbered" as the costing method Then each lot will have a specific cost. It will get you a little closer to what you want. I can recommend some other, more complex methods, but essentially that's the best suggestion.

Yes we are using them also, but lot numbered items behave almost exactly the same as serilized ones, so you need to play with inventory details and also when it comes to invocing, you have to create an invoice directly from sales order and we want to avoid that. Getting rid of serilaized and lot numbered items would allow us to simplify a lot of processes and code that we have, but COGS is the only problem which is stopping us from doing that.