It could be that your browser is giving you personalized search results instead of the true search results. Were you using different browsers or different computers when you searched?
To have unbiased search results on Google, use Firefox with the 'SEO Global For Google Search' installed. This extension was previously called 'Google Global.'
When that is installed, type the URL for Google's encrypted search into the Firefox browser:
This will allow you to see Google.com search results without your personal history involved.
Then, type a search query into the Google form and click enter. When you are on a search results page, click the 'SEO Global' icon which looks like a butterfly on the top left of your screen. From there, you can change the location of the search request to: USA, UK, Ireland, Canada or Australia.
Since most visitors to HubPages are from the USA, that is the location you should choose to see your Hub's ranking for a search query.