Figured I’d share this in case it saves someone else some points.
I’ve had the personal Amex Platinum forever and recently picked up the Amex Business Platinum. Booked about $8k worth of one way business class flights to Europe directly with the airline and was surprised to see I only earned 1x, not 5x.
Didn’t even cross my mind that the Biz Plat works differently here. Unlike the personal Platinum, you only get 5x on flights booked through Amex Travel, not when booking directly with the airline.
In my case I didn’t really have a choice since I was using a Delta eCredit and had to book on Delta’s site anyway. But if you do have flexibility, this is something to watch out for.
Posting so others don’t make the same assumption I did.