Re: Current points question
Because top 30 players have to play 4 ATP 500 tournaments per a year and they can't withdraw from them otherwise they get penalty zero point. It can't be replaced until a year, it will expire on 2013. April 15.
Isner didn't have serious enough reason for the withdrawal.
MC counts 500s tournament for some reason.
Isner did it in last year too, he withdrew from Rotterdam, reason was 'personal reason' and played in following week. Similar happened with the ranking.