Invoice Lines coming in through IDR - logic to match to PO lines

Summary:

Is there documentation available or can someone summarize the logic around how invoice lines coming in through IDR that are intended to be matched to PO lines get matched to those PO lines. I have reviewed the guide provided in Features, Recommendations, Guidelines, and Tips for Oracle Intelligent Document Recognition for Payables Invoices (Doc ID 2656229.1) and while it mentions that IDR is geared to recognize the following fields on an invoice line (Purchase order number, Purchase order line, Purchase order schedule, Item description, Invoiced quantity, Unit of measure, Unit price, Line amount), I can't seem to find information around logic that Oracle uses to match the invoice line for invoices coming through IDR to the PO line.