MBAir 12hr battery life is not true

No one seems to have mentioned/posted about this yet.

Prior to the Haswell MBAir part of the keynote was OSX Mavericks.

There was all manner of power saving methods in OSX Mavericks that were being touted to increase battery life.

and then the Air was presented with 12 hour battery life (13"). With some commentary on the Net that this is no leverage over Windows based Haswell devices.

BUT

the Air is still on Mountain Lion not Mavericks. So the battery life of the Air in 3-4 months time is going to go up even more.

Someone want to dissect the Mavericks keynote, cause they gave some guides to how much the methods reduced power usage. From my weak assumptions I would say an extra 4 hours.

What do all you equally sharp brains think about this?