When you post the manufacturing order - "Mark as Done" - Odoo post all product valuation and in accounting.

Whne you add material after closing, the extra cost is considered a price difference and finish product valuation is not updated. The logic is that this can be an extraordinary cost. If you want the fiish product value updated, you must use Landed Cost i the inventory app.

A normal process is to add components during manufacturing processing. Which is logic. You know what you are using.  Following best pratice process, you do not have any issues.

Hello 

I have also faced the same issue. it can be considered a bug.

Let's say during the MRP Process the user has picked one more component which is not there in the BOM and then forgot to add in MO after completing MO, if they are adding them it should increase the Main Product cost as well.

All the businesses have a different MRP Process. Other exp such as work centre, employee cost and overhead that can be treated seperately as well. However, the product component price should be added to the Main product in the MRP Process.

By considering this kind of user mistakes any improvement is there then it can be helpful in the MRP Process.

Hi,

In Odoo Manufacturing, the cost of producing a product is typically calculated based on the costs of its components, labor, and overhead. When you add more components to a product, the unit cost should logically increase to reflect the additional materials used in production. 

However, it seems that in your case, adding another component (Product D) to Product A in the Manufacturing Order (MO) doesn't result in an increase in the unit cost or value of Product A after the MO is marked as done.

This might be a default behavior in Odoo 16 CE's manufacturing module, but it's not ideal if it doesn't accurately reflect the actual costs incurred in production. 

To solve this issue, you might need to customize the manufacturing workflow or settings in Odoo. Specifically, you may need to configure the system to properly calculate the unit cost or value of the final product based on all its components. This could involve adjusting cost accounting settings, configuring bill of materials (BOMs) correctly, or possibly implementing customizations to address this specific issue.

Hope it helps