Amanda,
Each listing can only have 1 shipping profile as far as I know or can figure out.
Just my opinion, I hate it when sellers tell me shipping is refunded, for the simple reason, I feel they should get it right the first time and not MAKE me keep track of refunds due/paid/unpaid back to me. Its a real turn off for me, I would just rather look else where for what I want. My PayPal account already has so many transactions to sort through daily... Don't add work for your customers. Make it easy! :)