Amount does not match

[Tikweb22]

I created an order with API that has the total amount of line item 180kr, delivery charge 29 kr and the user has discount coupon 200kr. Every time I try to create the order with total_discounts = 200 it makes it total_discounts = 180. 
Can anyone explain why?

[GrahamS · Accepted solution]

Line item discounts and Shipping discounts are inherently separate entities, and at the moment there's a limitation on the ability to apply both at the same time to a given order. Because of this, the system is automatically setting your total discount to the highest achievable value based on the line items in the order, with that limitation in mind.