In the 'Flexibility and Freedom' section in CC, he says "You don;t have to adhere rigidly to the programs given earlier. Mix and Match. Invent your own routines." He also says to even change rep tempos if you want. His blueprint in the book is geared for strength only with no endurance. Some people are genetically predisposed to being strong and some to endurance and everywhere in between. Some will progress with little work sets and some will need more.