Yes the main page will also get pr and just check one thing that the sub page has one or two link of homepage it will better.
I'd like a summary as well. I'm dyslexic so it's kind of hard for me to read such small, bunched up letters like that.
If every page of your website has a link back to the home page then eventually the homepage will get some pr benefits. Deep linking is better than linking directly to the domain.
Getting backlink for inner pages is helpfull for both the primary /top level domain as well as the inner page.
The internal page would be passing some of the PR it receives to the home page. This is why you need to link every internal page to the home page.