DF: 765 mandatory points, 250 points in Buenos Aires (no consequence), 500 points in Acapulco (replaceable by a 250), 300 in Barcelona (replaceable by a 90), 10 in MC (no consequence) = 765 + 250 + 210 = 1225 points lost if Ferrer does not play any tournament.

RN: 1810 mandatory points, 1000 points in MC, 500 points in Barcelona = 1810 + 1000 + 500 = 3310 points lost if Nadal does not play any tournament.

Ferrer's total achievable is: 1330 points from non-mandatories (3 x 500s victory, 1 x MC victory = 2500 - 1170), and 3235 from mandatories (4 Masters victories = 4000 - 765). Total possible: 4565 points besides the ones he defends.

Nadal's total achievable is: 965 points from non-mandatories (3 x 500s victory, 1 x MC victory = 2500 - 1545), and 2190 from mandatories (4 Masters victories = 4000 - 1810). Total possible: 3155 points besides the ones he defends.

I think duong should verify my calculations though, so we can be sure if this is correct.