If you generated a label that has an unexpected postage because of weights, check a couple of things:
Head to your Settings, under Packages -
Using Return Magic, you are able to set a default package weight, which is added to your product weights to calculate total shipment weight:
(Product weight x QTY) + Package weight = Shipment weight
The (Product weight x QTY) is added for each different SKU in the return request.
- Under Default Dimensions, check the weight that you've added for your package - that might explain the discrepancies
- Under Default Weights, check if you've set a default product weight or minimum/maximum shipments weights
If that doesn't explain it, head directly to your Shopify products and check that the correct weight is entered. Note that if an order is placed before a product weight is updated, the product in the order will still have the previously invalid weight.