AP invoic- e interface Importing Manual tax lines

  Hi we are using Oracle R12.1.3 We are importing AP invoices from an external system into Oracle AP. The external system calculates the tax as well. We typically have one invoice line and one tax line on the imported invoices. What we want is that the system should create the tax line on the invoice based on the amount on the tax line on the invoice without recalculating the tax. What we noticed is that the system is recalculating the tax. Due to this, when there is a difference in the tax amount passed from the external system and