I think the difference with the PA book is that it is presented not as spirituality, or as a combination of science and new age mysticism, but as pure hard science. It also makes some very specific and very ambitious claims (in particular, that it can extend human lifespan by an average of 925 years). Further, on another site, the author claims that his theory can cure cancer and reverse the effects of heart attacks, which, unlike the life extension theory, are easily testable hypotheses.
When his suggested therapy has healed the scar tissue from a heart attack – generally considered irreversible – in a fully controlled, peer-reviewed scientific study then I will of course give his theories full credence. Until then, I'm afraid you'll have to count me among the sceptics. As a footnote, my first career, for more than 20 years, was as an advertising copywriter, and consequently my view is that any product must fully live up to the marketing claims made on its behalf.
