I know it's not realistic to expect this to happen I'm just throwing it out as a bit of GB math trivia, nothing more:
When the 1-15 sets hit 50 orders, everyone could change their single set order to five sets for only $17.56 more. If that's more sets than you need you could probably sell the extras for more than the $13.76 you would have paid. That's only $0.86 a key. I'm just thinking out loud to pass the time between F5 presses. ;-)