IMO, Google treats the passing of
PR, from directories, different. It could see all pages in the directory as having the same
PR and number of links. If this is not the case, there would be
major flaw in Google's calculation of
PR.
Let's say there are 2 sites, both could fit under one of 2 categories (like your site). Site "A" ends up in category "A" and this category has a
PR of 8 and only 5 links. Site "B" ends up in category "B" and this category has only a
PR of 5 and 15 links.
Why should/would Google pass more
PR to site A under this
false pretence?