
Yes, you are very rite but Google is changing from Last year and there is lots of influence of personalize search and search behavior , if you check with different data across world you will get different results and there is no wonder about it.
Google is started to improve (?) search technology and the results you are watching currently is its just part of Google updates. Now onwards, you have to improve your techniques and SEO methods to cop up with recent Google changes.
Now, onwards, you can’t ignore Google GEO Targeting , Personalized search influences with logged in or not and your presence at different Data canters, i think all this is started with implementation of Caffeine testing ( January 2010) and its rollbacks and rollouts.
you will see these happens more with Competitive keywords and keywords which are having more search ratios.
