AP Invoice Spreadsheet Approval Rules: Supplier and Non Supplier Invoices

I have few questions in Invoice Spreadsheet Approval Workflow:

1. We have Non-PO Invoice( only internal team creates non-PO invoices not suppliers) Approvals in the system which has few conditions based on Custom field( attributes at Invoice header). Rest all the sources invoice( including supplier PO matched) are auto approved.
2. Now we are going to introduce few more Invoice Approvals for supplier.
3. When I am trying to include supplier invoice approval rule( please note supplier only submits PO matched Invoices) , facing error that it’s not compatible with existing non PO Invoice Rules and move the new rule to other block.