I have that book. I have read until stage 3 or so. I am honestly not very keen on it..
I was expecting something else. Somewhere in the book (front or back, i can't remember), it says that it is a "science based" or makes reference to "brain science" or something. As far as I have seen, there is no science in that book. If there is, it is very little and very old. The book will certainly not appeal to those coming from a scientific background. Not for its science at least.
Having said that, it is a good meditation guide and it should be refered as such. A guide. No need to pull the "science" theme.
I would love to have access to your audio files.. Can you share?