I happen to have the Forumla and the Rampage Omega. I had no use for the Fan Extension Card 2 on the Omega, so I decided to give it a go with the Maximus. After all, both boards have the new NODE connector, as does the extension card. You know what happens in this scenario? Absolutely nothing. The extension card gets power, the fans spin up for about 10 seconds and the RGB headers light up, but there's no way to control them. The board doesn't see the add on card connected through the NODE connector in UEFI or any of the software provided by Asus.
Bravo, good job at supporting your own accessories.