The shipping calculation plug-ins provided by third parties to use with this e-commerce platform are all dysfunctional in that they calculate shipping separately on each item in an order and add it up. We are trying to find out how to fix this, but in the meantime I have added flat-rate shipping for three different zones: “local” for orders going to WA and OR, “California” for orders going to CA, and “General US shipping” for everything else. When you check out you will see the ridiculous USPS Priority Mail calculation as well as the automatically generated flat rate. Choose the least expensive shipping method, which I assume will always be flat rate.
Thank you for bearing with us as we deal with the shipping calculation issue.