After installing 10.6 on my MBA (rev.A) I've been seeing some strange behaviour from the battery: after being in sleep mode, the battery health sometimes drops to 40-60%, and results in very short battery charge, emptying the battery in 30 to 60 minutes. However, after a quick reboot, the battery is back to its original health levels. Anyone else out there with the same issues? And are there any ways of fixing/avoiding this sudden drop of battery health? Battery health (when not awaken from sleep) is 92% after 420 cycles.