Store URL: http://www.labellewinerynh.com/products/
WordPress version: 3.7.1
WP e-Commerce version: 126.96.36.199
Gold Cart version: 188.8.131.52
I did this: Set up UPS shipping for most physical items. Turned Flat Rate on for one lightweight item, charging $1. (Because using UPS for one card order - which would cost the price of a postage stamp to mail via USPS - costs $9.24 via UPS Ground, which is ridiculous.)
I expected WP e-Commerce to do this: Add the $1 flat rate fee for that item into the shipping total for the order.
Instead it did this: If shoppers buy a gift card AND a jar of jam (for example), they can choose to pay $1 total shipping instead of $1 + the cost to ship the jar of jam.
Now, I could instead simply disregard shipping for the gift card item (and eat the cost to ship it), but if I do that, the shipping calculator breaks altogether for card-only orders, and the order cannot be completed at all.