Good job !
It's interesting, but I don't understand why you didn't consider the semi-finals and quarter-finals in grand slams.
Grand slams are the best index of all.
Also being finalist in a Masters Series is imo better than winning an international series. And being semi-finalist is also a good achievement.
The ranking points are also too small imo and it's strange that you don't consider the criteria of consistency for that topic, whereas it is your issue.
For the Tennis Masters Cup, I think that the criteria (one or two losses) is not the best : the most important is whether you did win the tournament, be finalist or not.
If you only lose one match but in the semi-finals, that's not like winning the tournament with one loss in the 1st round (don't you think, Andy Murray ?
As for the Olympics, it was not as important in the past as it was last year : I think you gave too much importance to that tournament.