This would be the logical step if you were trying to peak for a 1RM at a meet, but if you want to be good at doing 5s, you have to do 5s. So the rep range isn't the variable to manipulate here. Now when you stop making progress, you have to decide correctly if the reason is because of too much accumulating fatigue, or not enough volume. In the first case, the variable to manipulate would be the intensity, or what's the same thing, the frequency of heavy workouts. That's the function that the advanced novice program serves, and one possible next logical change would be to move to a medium-light-heavy routine. Note that this is not the same thing as the TM, and your progress should still be faster on this than on the TM. In the second case, you should probably switch straight to the TM or a similar routine that includes higher volume workouts.