Today Google has released the data for the "Finalized Earnings" for January in my Adsense account and they are again down about 11% from the estimated earnings Google calculated before. Resulting in a loss of several hundreds.
Just to clarify, in Adsense there is a number for "Estimated earnings", updated several times a day and a number for "Finalized earnings", updated at the beginning of a month for the last month. You get paid "Finalized earnings", but stats are based on estimated earnings.
The Google thread I mentioned above has been closed and confirmed that there is a new algorithm to detect invalid clicks. There has been given a link to the following page:
After thoroughly reading the articles, I still have no clue why they deduct money from my estimated earnings. It would be great to have information (like a percentage of invalid clicks per inventory) so we can fix that. It seems I'm not alone with that problem.