The shipping price is based on the item's weight, so all your listings must have a valid weight. The weight needs to be updated in the listing's "weight" field and not in the item specifics (we do not read data from your item specifics).
When you connect your store to Hipshipper, we check all your listings for weight. if they have a weight, we move them to the new Hipshipper shipping policy.
if the weight is missing, we use the identifier you provided, to search amazon (and the web) for the item's weight. If we find it, we update your listing and then move it to the Hipshipper policy.
A 0-weight listing that cannot be updated by us, will remain in your original shipping policy and be given a weight of 70lbs. That is done to make sure the listing does not sell at a loss for shipping.
You will also receive a notification in your HipShipper control panel, asking to manually update the weight. Once you do that, we will revise your listing and move it to the HipShipper shipping policy.