We regularly create PO's from Sales orders for items that we Drop Ship. We also regularly have changes to either the PO or the SO. Once you auto create a PO from an SO, you are unable to make changes on either that update on both. For example, if the auto created PO needed an item added, you can add the item but when you save the PO, it does not save the item. It obviously also does not update the SO. Additionally, when an item is added or edited on the SO, that creates