Clarification on AutoInvoice Flexfield Uniqueness Check

Summary:

If we create two flexfields for line transactions, INTERFACE_LINE_ATTRIBUTE1 and INTERFACE_LINE_ATTRIBUTE2, and require that the combination of these two fields must be unique for AutoInvoice import into Oracle Fusion, I would like to understand whether the system checks this uniqueness only for each upload batch, or if it checks against all existing records, including previously uploaded data.

For example,