You give 56 as the official answer for "The Puzzling Page", but I remain suspicious of this answer. In particular, I guess the phrase "counts this new number of pages from the back" is ambiguous. To my mind, if you count back 65 pages from the last page of 120, you end up at page 55 not page 56 (i.e. counting back one page from 120 is page 199 not page 120).
Therefore, I stand by my solution which is page 78 of 165 pages.