well if he skips nottingham he will lose a significant amount of points....
actually,,,the winner of halle gains 225 points
when the winner of nottingham gains only 175 points
also,,,halle is a non-countable tourament for richard now
IF he wins halle, then he will gain points
in addition,,,i think the seeding of wimbledon will not consider the points that he will gain or loss at nottingham