Invoice Distribution Lines not Created... Invoice on Hold with Dist Variace

Hello....

  We have recently upgraded to 12.2.3 from 11.5.10. The Payable Open Invoice Import successfully imported the AP invoice and AP invoice lines. But the AP Invoice Distributions are not imported. I have also run the Invoice Validation program and still no AP distributions. The AP invoice is placed on hold with Dist Variance. How to successfully create the AP distributions using Invoice Open Interface? I made sure to populate all the required columns in both Invoice and Invoice Line interface tables.

  Also, I am not able to find the Invoice Line DFF in the Descriptive Flexfield window to enable the Invoice Line DFF.