Sometimes system receives historical transactions. For example a transaction file received on Feb 2, 2020 may contain a transaction that happened on March 3, 2019. Such cases happen when a transaction is disputed. If it is set to 'Yes', then system will not invoice such transactions. If it is set as 'Not Set', then system will prompt user to decide on the spot when invoices are generated. Recommended setting is 'Not Set'. If it is set to 'No' then all transactions will be invoiced irrespective of the date it happened on.
This can also be useful during onboarding process. For example, if you start using software on Feb 2, 2020 and you already have your cards running in the market, then you may want to skip all transactions that happened before Feb 2, 2020. If you do not skip transactions happened before your start date, then invoices may have incorrect calculations.