Before they killed the Upgrade Fairy, I went from a Balcony room on Anthem to a Grand Suite - over Christmas no less - for no extra charge!
Now you can 'Royal Up'. So, you buy a balcony for $5000, and bid on a Grand suite for $400 where the cost of booking was originally $10000, and if you win the upgrade (now a total of $5800), you "saved" $4200.
So .... how many suites are they actually selling at $20000?