Thanks for that Lurker. It is a better method obviously, although I'm not sure if the weightings are the way I would set them up. Ordinarily, by this point in the season the number of games takes care of all of your concerns.
The main criticism I have, which may or may not be valid depends on whether or not you can change the time period. The NBA site only allows the season to date, last 10 games or last 5. Because of all the changes with key teams personnel, it makes sense to focus on where these teams are now over the past 2-3 weeks, and how they will change over the next 4 weeks. It's more important to me to focus on these games, as the teams try to work the new additions into their play and at the same time be in a pressure situation of winning or getting chased out of the playoffs.
Teams change over time, and some teams develop to the point where they displace the teams above them. A good example of this is the Sixers, who have demonstrated that they are now a playoff team even though they have a below .500 record. The reason is that since they developed a new style of play and figured out how to win, they are now playing better than .500 ball. This change showed up in the point differential first, and now it's revealing itself in the standings.
And those who want to say this is simply the result of a weak schedule, they did beat Orlando, Dallas and Phoenix. Maybe not the best teams, but all three are legit contenders. When over the last 10 games they're winning by an average of over 5 pts, they're not the 15th or 16th team but the 8th best team in the league.