iPhone battery 3A345 vs 3A347

I did a restore on my iPhone and iTunes installed the slightly newer 3A347 firmware which very anecdotally seems to have improved the standby battery life. My phone had been losing about 70% of its battery life just on standby overnight. with the 3A347 firmware it appears to be just losing 5-10%. I don't know if it's made any difference to the in use battery life., and apps still crash and on occasion the phone has rebooted itself for the fun of it.