Pay on Receipt auto invoice - Invoice Summary Level - Site

We configured the supplier setup to generate one invoice per supplier site for all receipts.  Receipts comes every day and program runs once a day.  Instead of creating one invoice per site, the program is generating multiple invoices.  The configurations all looks ok to us.  Can members advise what could be the criteria other than invoice summary level if any that results in multiple invoices being created or we are missing any other critical setup in the process.