Output Account Moves for production

I need to understand why creating a production with same product input and output and some other products as input don’t result in a higher amount for the move.
Let me put an example, I need to transform a desktop table that have a missing leg into a full table:
Production Inputs:

  • 1 Table 10€
  • 1 Leg 2€

Production Outputs:

  • 1 Table

The 3 account moves and their amounts generated after ending the production are:
Account Move Input table 5€
Account Move Input leg 2€
Account Move Output table 5€

and Production cost: 7€

For my point of view the output table need to have the same amount as the cost of the production instead of the same cost_price as the matching input product.

Am I wrong? Which is the accounting explanation?
Thanks in advance for your time.

This is true but just when you do not have works that increase the cost of the production. In such case, the cost of the output product will be higher than the sum of the input product. The diference will be the work costs.

I guess you are using fixed cost price.