The Power Rankings are a complex calculation based on your seeding at each league scoring category. The numbers displayed within the power rankings are how many points you earned in each category during the season. (except Wins and total categories - which are the actual number of wins).
You can view the report in either 'Full' detail mode (which shows each individual category that is used in the calculations [along with the totals]) or in 'Total' detail mode (which only shows the total points accrued at each position). Regardles of which mode you choose, the calculations are still made in the same manner.
If you run the report for prior seasons, it will only calculate these points based on the regular season (weeks 1 through 12). Because it is based on total points scored, additional playoff games would cause an uneven playing field and would not properly display information.
The power rankings are provided as a utility to find where your team's strengths and weaknesses are. They have no effect on the overall standings, divisional rankings or other statistical aspects of the league. It is important to remember that these are based solely on points earned, so if you don't start the best player at a position for a given week it will impact your rankings.
How the Rankings are calculated:
Each category is sorted by the number of points earned. Points are awarded based on your ranking. The most points earned in a category are good for 24 points (24 teams in the league). Ties in categories are all awarded the same point value. (i.e. If the top 3 teams in a category are tied. They all get 24 points. The 4th place team would then get 21 points). The points are then totaled from every category to give each team a Ranking Points Total (the maximum ranking points total would be 936 points [39 categories * 24 points per category]).
The 'totals' for positions are used in the calculation of the rankings, but are there as a quick reference to where your position(s) rank amongst the league.