To me this just seems like another example of the official rankings being too volotile. There is no way Lleyton Hewitt should have been down at number 20 last week.
The official ratings are a volume based system which reflect activity as much as the quality of the player.
The ratings should be reflecting only how good the player is. That certainly wasn't the case for Venus Williams going into Wimbledon ranked outside the top 30. That was definitely more of an activity deflator at work.
There's many ways the rankings could be altered to do this, but the ATP seems to have an interest in ensuring players are as active as possible.