Can someone please advise what is the difference between the "1911 IOM census records" and the "1911 Isle of Man Census Summary Books Record which is now available on Ancestry?

I have been trying to find someone who I know was in the Douglas Ind. Home in 1911 and is not shown in previous release of this census but I believe, is due to be released in its entirety in January 2011 as per the 100 years embargo.

This person is not shown in the "Books Record" version.

Thank you