I hate Google Adsence its crap I have to say it you know your thinking it! at the moment I have no choice as I cant use YPN or Microsoft publisher network and have to use Adsense, But I got so sick of low paying clicks and false impressions showing that I removed the ads completely for a few days and then I put back on the ads and I noticed that both the impressions went up and the clicks being registered.
Did you added any channels in the ads before & after....else the content is changed...the earnings might depend on the channels & content where your ad displays.....but the impressions wont vary...its solely depends on number of visits..check your analytics............
I've cross referenced Anyltics with adsense, Anyltics says that I have "over the last week" 2300 unit impressions 1700 adsense page impressions which is strange to me. I have had over 10,000 visits 90,000 page impressions, I had two adsense ads per page in the last 3 weeks to my site from when it started but I have been using adsense for a long while before using on my recent sites.
Adsense says I don't get more than 129 impressions a day and very low paying clicks got one the other day for 1c
Have you tried replacing your adsense units with CPA offers? You can usually find good CPA offers in whatever niche you're working in. Higher payouts as well, just a thought.
The improved performance is just a coincidence. I wouldn't get my hopes up based on this if I were you.
Having said that Adsense is great! You just need to get the right amount of search engine traffic, make sure you have keyword optimized content and test different ad formats.
For ..... sake, the visitor does not even have to make a purchase and you still get paid.