Originally Posted by Pratik
If Ferrer does not go to any 250 or 500, he loses 250 + 50 + 160 = 460 points. The additional 160 points come as the 250 from Buenos Aires will be replaced by 90 from Doha/KL. (Acapulco, Barcelona, Buenos Aires -> Auckland, Bastad, Doha.)
So, now it's 1235 points for Ferrer to defend.
3310 - 1235 + 1465 = 3540 points must Nadal do without Ferrer defending any point. 4615 if Ferrer defends all points.