I believe it is for both global and U.S. Amex Plat. I booked one through Amex Travel while it was still 10% off, using U.S. Amex Plat. Amex's price is the same or just a little cheaper than Etihad website price, but not really 10% off. For higher price ticket such as business class ticket, many OTA offer cheaper price than Amex's 10% off price, but you get 5X points if you book through Amex or Etihad directly using your Amex Plat card.