There are two issues that are causing the purchase order template to appear this way.
When looking at the purchase order displaying the two extra unwanted columns, it was found not to be an issue with code or the purchase order itself. What we have found is that the vendor had "Purchase order prices/amount" checked under their vendor account, which is causing those two extra columns to be displayed. Unchecking this checkbox and re-posting the purchase order should fix this issue for the existing purchase order and all future purchase orders.