Well...they say "You made 10,000 views and you get 0.88€ per thousand views." 10 minutes later they say "Oh sorry, it's not 0.88, it's only 0.76€. We have to take that one click that made you 1.24€ away from you again"
So yes, they only take away estimated revenue, not actual money. Which is okay, since it's only estimates. Can still be upsetting when you see that you got a really big hit and then it's gone again.
Fortunately I don't even notice that anymore, since I get so many advertisement clicks now, that I don't even try to differentiate what click made how much money. Was different when I was smaller and every advertisement click made a difference to me.