It may sound very strange but I faced an unusual thing yesterday. When I signed in my adsense account my daily earning was 75 and after I checked some perfomance reports and returned adsense main page and I saw as 40 and signed out and signed in again and it was still 40. Have you ever faced this kind of issue before?
Yes, this can happen. Adsense keeps regularly monitoring the clicks and the cost of multiple clicks are adjusted.
I would like to thank you for your quick answer. Actually I have one more question: Google places high paid ads to high traffic web sites. If your website traffic is high then you get more for each click. If we have more than one website and let's say one of them has PR:7 and other one is PR:1 with low traffic. Do we get similar earning for each click since we have same adsense account on each website or different due the traffic. Shortly, I would like to learn if google take cares of each website traffic or your ads page view in your account.
The cost per click does not depend on the quantity of traffic, but more from the quality of traffic (location, etc). There is no relationship between PR and cost per click as well. A PR 0 website can very well get much more than say a PR 7 website. It depends on many factors, even beyond niche. Sometimes an interest based ad on a low performing niche can give you a lot per click. Location is the key most of the times (traffic from US, UK, Canada, Australia pays more). Ads for each of your websites will be different and as I said before, it wont be related to PR. Hope this helps.
As far as I know the CPC received is highly dependent on amount an advertiser pays and how the ads are targeted in AdWords. Beside this, there is an bidding system that calculates the CPC. Things like geo location, the topic of the website, the keywords on the page and so on. In addition, the amount we get pay click is also related to the value that Google sets for each user. So for 2 different websites, the CPC for the same ad can be different. Nevertheless the CPC is not related to the quantity of traffic, but to the quality of traffic.
hello there short answer yes they can read here : https://support.google.com/adsense/answer/190436?hl=en