Quite often when I process foreign orders with items on sale the customs value is incorrect, even though the pricing listed for the products and the subtotal within the orders details is accurate. Half of the time I can not even figure out where SE got the prices. it seems it should be pulled from the order as I may offer a special for that customer only. I have had a couple of customer complain about the taxes/customs paid as I did not catch this before shipping the order.
correct product details/prices (example my order # 114583 shipped on 1/24/20 - no coupon etc on this order for that to be a reason)
https://cdn11.bigcommerce.com/s-hqlnzi/product_images/uploaded_images/order-114583-details.png
incorrect customs total
https://cdn11.bigcommerce.com/s-hqlnzi/product_images/uploaded_images/order-114583-customs.png