I think what most agree with here is this is all free funds from RCL. They applied the obc based on the room you booked now, not the one you had. As they should have. It was nice they extended an additional $50 to you when they didnt need to but did it as good will. Had you went on your original cruise its a non issue that they messed up and duplicated the others OBC. But that duplication was caught and corrected. We are so quick to scream when RCL messes up but in this case they gave you what they should have and then some when they didnt need too.
Continuing to monopolize customer service over this is wrong in my opinion.They applied it according to the parameters of the program. If you found a sailing with equivalent fare in a balcony, you would have received the 100 and so would the others (not the 200). So I fail to see how RCl wronged anyone.