If I add a product to the cart, with a price of 590,- then the shipping cost is 0,- because the shipping is free over 500,-

If I add a promotion with 20% off, the shipping is still 0,- even though the price of the item is now 470,- and therefore under the 500,-. Then the shipping should be 49,-

This has already been ticketed as a bug, but declined with the message "We have concluded, that the behaviour you describe does not meet the criteria for a bug and instead consider this suggestion to be an improvement."