Duplicate Invoicing

Can someone tell the best practices that we should be considering while incorporating logic to avoid duplicate invoicing ?

Invoice source could be scan one / AN / P2P internal.

e.g if the original invoice number is - 123 .. system should not allow a new invoice number 123a / $123/00123

My thoughts to handle this are via :

1. Set Application.Invoicing.AllowResuingInvoicingnumber parmeter to false.. But I believe this would help on AN based invoices . would this parameter also have control on invoices coming from scan one ? as those are sent via AN as well ?
2. Configure approval flow to check -- manual overhead more.
3. Periodic reporting and validation via analysis.