So in Netsuite, we use Pacejet to handle the final mile of fulfillment. They write back shipping cost into a field called freight cost and we have a workflow that automatically copies it into Shipping Cost on the item fulfillment. On the sales order side, does the shipping cost field not automatically get updated with the sum of the shipping costs from the item fulfillments?

I don't think so... And I wouldn't want it to by default. In many cases you might not be able to change the shipping because you quoted the customer a shipping number and can't go back for more money.

I get why it's not there by default. For our business model, customers are usually on terms and shipping costs are passed on directly, not agreed upon. I wonder if this can even be done in a workflow. I don't see a way to reference the IF record from a SO workflow. Might have to be a script.