That means your ads wasn't on the top before. So how they worked well for you?
Actually it is not just having the ads on top, you need to keep changing the size every once in a while and change the position as well to get the best results...
Well, For me I think ads shouldn't be uncomfortable for readers. That's it. That's why I used to put ads on sidebar or on the top bar.. That's it. I don't used to change the positions at all.
