Thank you for your answer !
One more question though, why the Live Ranking have taken off the points frome this week tournaments ? Is for resetting the results of last year pending to this year results ?
Yes that's right. If you look on the ATP profiles for the players the points from the previous year will have a drop date - usually at the beginning of the current year's tournament.
Here is Andy's profile showing the drop dates for his points: http://www.atpworldtour.com/Tennis/Players/Top-Players/Andy-Murray.aspx?t=rb
The exception is with Davis Cup, where the previous year's points drop at the beginning of the month in the current year in which they were gained in the previous year. So Andy's 65 points from the tie vs Italy will drop at the beginning of April, at which point he'll drop the DC points from his countable tournaments and include the 90 points from Dubai in their place, until he gets a higher points score from another 250/500 tournament (hopefully in Munich!)