You can just say Thanks very much. Another way of saying "thank you all the same" is "thanks, but no thanks" where you are making it clear that you are refusing what has been offered to you.

Yes, they're the same. They can be used either when politely declining an offer, or when thanking someone profusely for something (when reiterating how grateful you are, and maybe they're shrugging it off like it's no big deal, for example). You can always use "thank you".