I did a mock booking with a computer in incognito mode and figured the final dollar amount without cheers. Then I did a mock booking with my normal computer and my rate code for Cheers on Us and it WAS more expensive than booking without and then buying it.
but...
I also did the same thing for the rate code w/ $500 on board credit and the booking with the rate code for the OBC was $300 higher than the normal booking - so we spent an extra $300 to get $500 - and I'll be using that OBC to buy Cheers anyway LOL