I am wondering what the different percentages really refer to in the battery usage section. I mean...in total I see more than a 100%. So it is easy to presume that it doest mean a certain percent out of 100%.
On my phone (ICS) the apps seem to use less than 100% in total. These must be rounding errors: if you had three apps each using a third of the total, that would be 33.3..% for each one. Android would round this to 33%, so the total would be 3*33%=99%.