I think that funkybunch78 is spot on. When I took my last test, I created my indexes to prepare for the sample test, and preparing the indexes made me review everything. I used the practice tests to figure out where my weak areas were, and most importantly, where my indexes were weak. Going back through all of the areas where my index were weak made me review the information a second time, which I think left me very prepared for the test itself. Between the review and the indexes, I finished in about an hour and 15 mins and I found that the areas that I didn't have to go back to the book very frequently at all because the creation of the indexes had kept so much stuff fresh.
CISSP, CSSLP, MCSE+Security, MCTS, CCSP, GPEN, GWAPT, GCWN, NOP, OSCP, Security+