Color it odd then as it most definitely is correct. Congratz OP. That's somewhere in the order of 8,000 -11,000 Gold required to achieve that rank for an item that didn't stack.
Effectively, there was a better prize given to everyone for free today
Feel better?
No? Well, take heart. ITunes refunded an amount similar to what you expended to a team-mate in the same boat. Apparently when an advertised prize doesn't actually do what it says on the can, you have an open and shut case in your favor. I suspect Google are equally accommodating.
Until GREE put in a disclaimer: these modifiers won't stack or actually address the issue, if anyone finds themselves in the same tier again they are better off skipping the flippant support.