We have a retail website using Wordpress with WooCommerce and we take payments using SagePay (now Opayo) 

We would like to add coupon codes that give customers a discount (say 10%) But, when we import these transactions/invoices into Sage50 the negative value (-10%) is seen as an item but appears in the Sage50 accounts as a positive. This would mean that we would have to manually adjust all coupons within Sage50. 

I myself doesn't use Sage50 but I am doing the Wordpress side of things and can't have it importing items/coupons that are seen as minus amounts.

Does anyone know how to do this? Or can someone help?