So initially it was suppose to be 16 eps, then the writer's strike brought this season down to 13 now they are adding an hour to the end of this season with a two hour season final, and making the next two seaosn 17 eps long, which makes up for the 3 lost eps of this season. WOOO
Great news! I still think going from 24 down to 16 was a bit harsh... maybe 18 would have been good. But in the other hand I guess cutting 3 seasons short has sped up the story telling considerably which is good.