Help! Paypal Error Code 10413 (When Using Discounts) Causing Havoc

[EXCORP]

I am pulling my hair out trying to get this fixed.

Using Paypal express checkout 1.3.9 (prestashop version 1.6)

 

I have a discount on a customer group (because I have affiliates) and no discount on customers. 

I am running a sale this weekend, with a discount on certain categories. 

When someone goes to checkout with any discount or voucher applied they get this error
 

Unexpected payment error

Unfortunately, an error occured while communicating with PayPal.

Short Error Message: Transaction refused because of an invalid argument. See additional error messages for details.
Detailed Error Message: The totals of the cart item amounts do not match order amounts.
Error Code: 10413
Please contact our Customer service and mention this error code to get this issue resolved.

 

 

IT is driving me CRAZY that I cant figure out how to get this fixed. Loosing sales big time today because of this. ANYONE help?? 

 

PS - I would love to simply go to paypal standard, however it doesnt take me to an order confirmation page (goes to order history) and for my affiliate tracking I NEED it to go to order confirmation. Hence why I had to go withe express (which I cant stand) 

SO - If you know of a way to fix the paypal error 10413 OR how to change paypal standard to go to order confirmation after order I would SO very much appreciate it. Our "black Friday" sales in the US are huge and Im loosing sales over this.. 

 

REALLY need it fixed asap if anyone can help