The book is geared to supplement what you learned with NEW, which is free and available on the articles section of this site, and other places- I do believe that a trance practice does enhance all sensations, but if the purpose of the book is to teach you these techniques, the trance induction is something you don't have to do until you've actually learned the techniques themselves.
I don't think there is an 'old' way and a 'new' way to do it- you learn it how it feels right for you (for example, I still prefer a 'sponge' instead of a blue ball) for prestimulating, and I prestimulate legs and arms before I do anything at all. It's just a progression of things you can do, nothing is substituted.