Home page has much lower PR than deeper pages?

Why is PR lower for home page than deeper pages?

[Serpent]

My company sells sports, theater and concert seats. Some of the performer pages (Shakira, Monty Python's Spamalot) that are a layer deep have PR 4 and 5, which I've seen grow up from nothing in the past few months. However, the home page stubbornly remains PR 3. Everywhere else seems to be the opposite, that is a high-PR home page with the PR trickling down to the deeper pages. I have to think that this is hurting the site in the SERPs. Does anyone else have this problem or any ideas what the cause of it could be?

[sem4u]

Are other sites linking directly to the performer pages? That could be the cause of them having a higher PR than the home page.

[Serpent]

There are links going to the performer pages, but there are also links pointing to the home page from other sources, including from performer pages-->home page.

[tedster]

It's not that uncommon to have some deep page prove extremely linkworthy and top the Home Page in PR. For example, a technical section of a web developer's site might publish a valuable resource, a reference list, a tool, whatever, that attracts much link attention -- but those same sites would never link to the Home Page.

Sometimes Home and Deep may both show the "same" PR. But remembering that PR is really calculated to many decimal places, Deep may be beating Home (5.9485766322 vs 5.0239162743, but they are both PR 5).

There's no reason this PR scenario would harm a site in the SERPs. Deep pages still circulate their high PR back through the site (assuming they have navigation links) and in general, high PR deep pages are helping, and not harming.