It's turn a page every two seconds that equals one second per page therefore 15 minuts is roughly what such a book would take. Given that Peter mentions thin pages turning is probably difficult so time wise I'd say he's doing fine.
As Iam2 has said, check the other factors if they are fine by you then all is okay.
Going faster has actually helped folks to stay in PhotoFocus better some find turning one page every second too slow and they get distracted. Rate is not as important as having a rhythm that is fairly consistent. Slow, Slow, quick, quick, slow is not one that helps you stay in the Accelerative Learning state though you might look cool on the dance floor.
Alex.
