Of course, your question makes sense, Tom. Let's review the details you need to change and add to your bill.

There's no restriction in editing the item quantities. When you copy the purchase order to a bill, it will take you to the Bill page where you can change their quantities. Is there an error when you try this step?

As for the tariff and freight, you can create items for each and assign their corresponding expense accounts. Then, add them, like how they are shown on the actual transaction. If their amounts are in the percentage formats, just get the converted values and them to your bill. And yes, they will be included in your bill payments.

Let me know if you still need help with your inventories.