OSN (XML GATEWAY) Invoices with Tax LInes - Prorate Across Flag in R12

Hello -

I am trying to resolve an issue with importing AP invoices delivered via XML GATEWAY (OSN).  When the invoices are delivered to the Open Interface, the Prorate Across Flag is populated as follows:

Freight Line = Y

Item = NULL

Tax Line = NULL

After importing the invoice, the invoice has the following lines:

FREIGHT = 10.72

Item = 209.18

Nonrecoverable Tax = 0.51

Tax Rate Variance = 9.95  (Total Tax is 10.46)

It looks like the .51 is tax allocated to the Freight LIne.

However, I am expecting the Tax Rate Variance to be the full tax amount (10.46) and no Nonrecoverable Tax line

If I manually update the Prorate Across Flag column to have 'Y' for the Tax LIne prior to import, then I achieve this result.