The whole point of doing a trademark availability search is to avoid what the law refers to as likelihood of confusion. You can read on the USPTO's (The US Patent and Trademark Office) website: "A complete search is one that will uncover all similar marks, not just those that are identical." http://www.uspto.gov/trademarks/process/search/

So you have to answer the question: Are there other similar trademarks, being used for similar or related goods/services? If there are, your new name may be infringing (violating) third party's trademark rights and they could force you to change name and even claim damage.

So the availability search should find as many relevant name problems ("killers") as possible with a minimum of search results to review (i.e. avoid the "noise").

On the surface this might sound pretty straightforward. But when you study how the courts have ruled on various likelihood of confusion cases, you begin to see the challenge.

Is "Halisyn" similar to "Habixin"? - Yes, at least in one ruling.
How about "Chamex" vs "Kanex"? - Yes.
"Volvo" vs "Solvo"? - No.
"Inolog" vs "Inulac"? - No.
"Pervasive Software" vs "Powered by Pervasic"? - Yes.

We will find these similar trademarks for you, with a minimum of "noise". But you or your trademark expert will have to decide whether they pose a real threat to your chosen name or not. See: What should I do with the search result?