Why do some of my pages count as backwards links, others don't?

Seems to be no rhyme or reason

[spaceylacie]

My site has been online for about 6 years and has about 300 pages that contain outgoing links. On about 1/5(60 pages) of the pages I can click on any of the links, view their Google backward links and see my site as one of the first listings. One other pages, my link to them is not counted. By the way, when my site is listed as a link back, it's always one of the first ones listed.

There seems to be no rhyme or reason for this. All pages are similiar, just different specific topics, all related to the main topic, all have a PR between 3 and 4(PR doesn't make a difference), all have a mix of sites that link back and sites that don't.

I'm thinking about manually going through each page to find out the exact percentage of sites(and their Google PR) linking back to see if I can identify a pattern. On some pages, almost every link is linked back, and my backwards link to each site doesn't count. On other pages, only 2 or 3(out of about 20) link back, but almost all of the 20 listings(when I view their backwards links) count my site as a link back.

Any ideas on how to get more of my pages to count as backwards links?