Thank you for the additional insights on your concern, @AWBEL.

Allow me to fill you in on everything about changing inventory assets account for an item.

I can see that the transactions on your screenshot were made before you change the inventory asset account on your assembly item. Please know that when you change an inventory asset account on an item, the transactions related to the Build Assembly will reflect the account after the changes. 

Since your first set up was Inventory Asset, it's the reason why your build assemblies showing the inventory asset account. You'll want to make a sample build assembly to check if the Finished Goods Inventory account reflects in the report.

You might want to check out this article to learn more about inventory assets tracking: Understand inventory assets and cost of goods sold.

Please let me know if you need clarification about this, or there's anything else I can do for you. I'll be standing by for your response.