Okay, so they kidnap Fischer and make him come up with some random numbers. This feeds his subconcious the numbers later so he can unlock the safe right? My question is the architect already built the hotel level, so how do those random numbers become the rooms they need, and how does his mind effect the design of the dream? Wouldn't that be part of the plan at the start and not up to chance?

i had a similar doubt about it

http://www.nolanfans.com/forums/viewtop ... &start=150

Recurring motifs are just small details like visuals repeating, this has actual plot relevance important to the heist plan. So Eames wrote them down and gave Fischer the numbers again into his mind. Got that, sure. But then someone ran upstairs and stuck them to the doors for each room or what?

Isn't it possible Ariadne and Arthur changed the layout of the hotel? They were together, she is the architect, he is the dreamer, and he asks her: "This room is directly below 528?" It wouldn't have been a giant change, you just have to change the numbers of the rooms, right. So Ariadne knows the layout and Arthur can change the layout, and that's why he asked her if they were in the room below 528 (to make sure he changed the layout correctly?). The fact that the room below 528 is room 491 is a nice detail in my opinion, but not necessary.
It's like when Eames added an air duct system.

Ariadne teaches the layout to the dreamer (Arthur) so did he change it? It's possible but seems like a risky thing to leave until they are inside, as well as after using Mr Charles, and they didn't mention anything needing a design change during the mission even if it's used during the earlier teaching scenes. Details seemed to be important to working it out, like the Penrose staircase.