netmeg - 6:12 pm on May 22, 2012 (gmt 0)
But without status information from Google I'm shooting in the dark.
There is no such thing as status information from Google, and don't assume you will ever get it. That's what AdSense is, and it's not changing any time soon. It will always be shooting in the dark to some degree. Google gives us a system where all we have to do is place some code and wait for the money (assuming we stay in compliance with TOS). But in exchange for that extreme ease of use, we give up a boatload of control, and pretty much all communication.
If your AdSense suddenly tanks, you can use your limited options (experiment with styles and placements) to see if you can help it along, but that's about it. That's the program they offered, and what we signed up for. There's no "AdSense isn't working so maybe they'll fix it" - just occasionally some delayed stats.
There's no incentive for Google in changing this, because the advertisers are the important ones here, not the publishers.
There are a lot of reasons why earnings fluctuate, and there's a lot of posts here on that topic - it isn't *only* because of what Google does. But Google isn't prone to slicing their own earnings either, so if they do make some change, they're probably getting the best of it somewhere - just not from you.