Bdgregory,
The contract between seller and common carrier and the contract between seller and buyer are two different contracts.
Just because the seller agrees with the carrier that he bears risk of loss as it relates to their contract, he does not necessarily agree that he bears risk of loss in the contract with the buyer.
The contract between seller and common carrier and the contract between seller and buyer are two different contracts.
Just because the seller agrees with the carrier that he bears risk of loss as it relates to their contract, he does not necessarily agree that he bears risk of loss in the contract with the buyer.

