Yes, it's possible, JR. I'll guide you on how to do it.

You can add a subtotal item after Lladro-1415, so the calculation for the fee and the commission will be based on the sub-total amount. To do this, just add a new item from the Invoice page, select the Subtotal type and name it as Subtotal.

The outcome will look like this:

If you want to check the total commission for a certain period, you can go to your chart of accounts. Then, run a quick report of the account that is associated with your commission item.

Feel free to reach back out if you have other questions about your transaction.