Adding Document Discount to SO Import Scenario

Hello,

trying to add a document level discount to a SO Import Scenario where the SO could have multiple lines. 

Not sure exactly where to put the discount in order of operations, but i’ve been trying to follow the order of tabs in SO screen.   I have also tried to put the discount above the ‘line details’. 

In this example the SO will have 2 lines, and i’m getting following error on the 2nd row (this example puts the discount after the ‘line details’ are entered - see XML): 

I have attached the XML for reference. 

Any help is appreciated!

Cheers,
k2​​​​​​​