This setting applies when you change the supplier of an invoice in Verify, and there is an invoice definition associated with that supplier. Use it if you want values that were found on the invoice before reinterpretation copied back to the invoice data after reinterpretation.
Setting CopyOldValuesWhenReInterpret to 1 is useful if you want to be able to choose whether to keep or discard the values captured before reinterpretation. The fields that are not green after reinterpretation get the value captured before reinterpretation (regardless of status). So this is good in a system with many unlearned or poor definitions.
Otherwise, in a "well tuned" system, the newly selected supplier (invoice definition) should generate the best field interpretation. Field interpretation done by the "wrong" invoice definition is less reliable than field interpretation done by the new definition, even if the selected (correct) invoice definition cannot interpret a certain field.
1 (on – values that were found on the invoice before reinterpretation are copied back to the invoice data after reinterpretation)
0 (off – values that were found on the invoice before reinterpretation are discarded – default)