Splugged - 6:23 pm on Oct 7, 2012 (gmt 0)
I just finished all necessary tests on my side.
I am tracking hundreds of keywords (and variants) and now I'm pretty sure... something is wrong (I cannot say which side, mine or G).
For many keywords, ranking on G does not match targeted page.
Just an example...
Page TOT - Product TOT
Test result: Yahoo, Bing, DuckDuckGo, Blekko, Ask, G referrals, G custom searches and many other "minor" SE -----> targeted page, ranking very good (also in G custom searches).
G mainstream (every domain) -----> ranking poor, and total unrelated (to kw) page.