We are running smit 3.88 on dnn 04.09.04 I have shipping set by zip code. If a user tries to check out without selecting a dropdown for shipping it will display an error saying to select a shipping amount. However, if a user selects the shipping method, but does not click calculate shipping, then they can click checkout and not have to pay any shipping. This is only in DNN 4 versions. Do you have a fix for this?