Problems with "discount value" Shopify Teamleader integration

I al trying to connect my shopify to my teamleader to automate invoicing. There is 1 field in the aggregator called “discount value”. I keep running into problems because this discount value can’t be 0. This means all of my orders with discounts go through fine but everytime an order doesn’t have a discount and the value “0” I get the error "value should be a positive number. Anyone know how to fix this?