Hi Johnny,

I believe you also need to know if, from the accounting perspective, the $20 will be booked in tax account or in a normal income account. If the first is true, then you need to have a product like "Tax on xxxx", where the "xxxx" will get the name of the product to be purchased and the price will be calculated according to that product. If this is the case, in my opinion, you'd better have two lines on the purchase order, one for the main product and the other one for the "Tax on xxxx"; the first line will have the quantity of 0 and the second will be calculated according to the price of the first line. The product "Tax on xxxx" can also be optional product so that it can be triggered every time you add a new product to the PO. I hope I could explain what I mean. :D