Smart Pricing "black-box" techniques are definitely a cause of worry for Adsense publishers. I have personally seen my earning drop when I started showing Google Ads on another less-popular website. Once I removed ads from this website, it took about 7-10 days until my earnings graph hit the normal mark.
I wish Google had been more open about Smart Pricing. AdSense Publisher Support did try to clear the misconceptions but that may not be enough to satisfy Publishers.