Definitely coming from the same location. I've had some days when a bunch of clicks were very very low too, but it's very rare.
certainly.... and it it depends also on how people reach his site.... if it is organic then he should have a good cpc..
There are a lot of clicks that are not paid because are fraudulent. Why am I saying this ? Because a lot of people use proxies and dynamic IP`s to click on their own ads (this might or might not be your case) , but there are a lot of people out there trying to cheat. Therefore Google doesn`t pay clicks done through proxies. As somebody was saying earlier Google`s Strategy on pricing is very complex. If an advertisers traffic sent through Google doesn`t covert you can be paid very little. Now the question is "Does anyone know how much is being paid for an ad?" and "What is the publisher`s share?" , the answer is no. And it`ll always be a big no.
Google might have considered those clicks as fraud clicks. And That too low if you have Genuine Clicks.
It happens when the same user clicks your ads 10 - 20 times or more, but this would be a problem if it was happening all the time.