That will not work if you want also to migrate the PO with invoice status while will post to vendor as transaction.
How did you upload the opening balances?
Just Gl or also vendor and inventory balances.
If just Gl, the. You can post PO s and reverse the Gl.
If vendor and inventory, then you need to reverse the vendor balance and remove from the inventory with to use the inventory journals.
I do not advise you to change parameters.