User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-1515612-20130221033240/@comment-4430596-20130221174836

Some scenes does not necessarily mean POV. Due to dreams, Katropis, and the like, we can see some of what is happening in Tartarus without giving Annabeth and Percy a POV. I don't think they will get one as it would be hard to capture Tartarus in writing and it's easier to just show the events of the other 5.