I believe there are 2 issues with your question.
I checked the data for the one example you provided and found no search volume, I assume this isn’t a real example. Why don’t you provide a real example so that we can confirm that you are grabbing the right data?
The second issue is to do with how you are interpreting the data. I haven’t found any significant issues with Google reporting incorrect data, despite PhilipSEO’s assertion. I think the problem is in understanding exactly what the data represents. It is search data, not click-through data. And yes the data will include all types of searches including searches performed by webmasters checking their rankings and automated tools masquerading as real users. So you may not be able to rely completely on the data, it doesn’t mean the data is incorrect.
Having said that, I find the data for most keywords to be spot on, however, you do want to keep an eye out for outliers. I recommed that you set up a temporary PPC campaign to test your assumptions before making any huge investment in time or money. That is the most cost-effective way that I have found to test for data outliers.