Nadal will play Rotterdam also I think
His 5th best is 55, and if he wins AO he'll trail by 100 points (assuming Nole beats Fed - must add that I find that scenario extremely unlikely). So he needs 155 points from Rotterdam, which equates to final.
But then again, Fed must defend all the points from Dubai, and even if he wins it again, he can't really prevent Nadal of reaching the final at least. So, in the case of Nadal beating Jo and then Joe, it's likely he'll assume #1 for a week or so, until IW & Miami, where he defends 500+125 points and Roger just 5+75.