possible calculation:
200 wpm (avg) * 60 m * 10 h = 120 000 words in a book
Photoreading:
200 min = 1/3 of 10 hrs
120000 words/200 min = 600 wpm, which of course is 3x the original wpm
so, if you wanna avg 12K wpm (reading same amount of material):
120000 words/12000 wpm = 10 minutes
So, this in this 10 min, you would preview/PR/activate and get 75% comprehension, which isnt really probable unless you have spontaneous activation (activating takes at least 30 min for once thru)
so, i think when they say 25 000 wpm, i think they mean ONLY the PR step....
...unless i'm totally wrong. 
