What they handed me at the front desk (note the room number):
What I saw when I got off the elevator on the 11th floor:
A close-up of that sign since the photo was blurry (just wanted to show there wasn't another sign nearby or anything in the photo above):
So yes, I was confused. After a few minutes of wandering the hall, I actually gave up. Oppressively tired, feet hurt, hungry, crabby. I just went down to the lobby and asked for a room on lower floor. Thankfully, I didn't get x10 (I got 618 instead). Whew. Problem solved.