If I had to hazard a guess I would say that google has increased the PR bleed from 15% to around 23% for front page links.
They will probably play with this value a fair bit and see how it affects the rankings, they will also be devaluing sites that only have homepage links.
Wont affect you much if you are deeplinking, however if your mainly linking to frontpage you will take a serious hit.
Just focus on traffic & Serps, PR is no longer the cornerstone of SEO and focusing on PR is a waste of time.
And remember Deeplink.
Didnt I say this before a few times?