Don't be evil, what about being outright stupid?

Recently i have been running a Google adwords campaign and saw some silly mistakes in my account. I am kind of sure, i am not the only one who has faced this issue, i am also sure Google would compensate for this.

So what happened here is this, i have bid a maximum of 0.04$ for a keyword. So ideally each click should cost me 0.04$, but Google has charged me anything from 0.04$ to 0.06$ for each keyword.

Its easy to understand by just looking under the Current Bid, Clicks, Avg. CPC, Cost columns for all keywords in the screeshot i am presenting below.
The question is if i have bid 0.04$ for each click, and i have recieved 1 click, how can the cost of one click be 0.05$. Or am i getting my maths wrong?

I have uploaded a screenshot you can click to see in full screen below. Take a look at this screenshot here

The bigger  question is that this is not a startup company who has just started operations and facing some operational glitches, there have been billions spent on Google adwords, most by folks who are not that analytical or tech savvy to look at the data Google provides in great detail. How many millions have passed through to Google this way?

Incase i have just got something horribly wrong please let me know!