Okay, here's the deal with that...Google only goes by their own internal analytics. Outside trackers like seo tool and wordtracker only sort by the traffic of their users...not the overall search engine results like people think. That's why there is a difference.

Use wordtracker and seo tool are basic at best...not a tell-all/be-all, written in stone counter.

The best thing you can do is use google's internal adwords keyword tool...It gives all of the best stats and requirements for google because that is their tool...it's patched into their algorythms.

Here's the link: https://adwords.google.com/select/KeywordToolExternal