So far, the only way I can see:
United Parcel Service (14.20lbs) (2nd Day Air): $88.39

on the checkout page is if I add Quantity 2 of products_id 121 with a 2lb attribute on it ...

So a 4lb item with a 2lb Attribute adding the Tare Rate that you have set of 10:1 and the Handling 4.00 ...

That gives a weight of 14.20lbs ... what is doubled here?