At 4.00 pm we had 3.511 impressions, 178 clicks and 41,71 $ ... 6 hours later (10. pm)we had 6.273 impressions, 312 clicks and 41,78 $ ... this is an effect which happens every day, but never extremly like today ... any explication? ... 'smart-pricing'? ... or simple normal?
Could be cpm ads, could be the clicks are coming from the opposite side of the planet, and Google decides they are less likely to buy, could be the ads they have selected don't work on your site. Lots of possibles!
Adsense earnings are a roller coaster, and you should never judge earnings on the basis of an incomplete day's figures Sometimes stats take a while to update, so you can't really be sure what you have earned until a fews hours after the day ends. You can't *really* be sure of earnings until they are in the bank.
It doesn't look like smart pricing to me. If you read older posts on the smart pricing issue most people believe that it is a discount assigned on a weekly base, not at the end of each day.
I could think of the following reasons:
Someone is clicking on your ads in a fraudulous way on a daily base and that is detected by Google, those clicks are automatically discounted.
If it happens at the same time every day, it might be because of clicks from a specific country where people bid for lower prices (in this case you should still earn more than $0.07 for more than 100 clicks)
Your best paying advertisers run out of budget at the end of each day and those ads are replaced by either CPM ads, or PSA's (public service ads)