Hello,
. I could make it update the coupon if I delete the current coupon, but the discount will still be for the previous coupon and not the new one. This issue is fixed when you refresh the page, though.
A solution can eventually be to directly set the "Address" and "Coupon" action on different steps through your checkout workflow via "Hikashop->System->Configuration->Checkout".
Also, the checkout workflow should actually check your coupon loaded and prevent you to apply a coupon that shouldn't be applied to that order configuration.