There is built in motivation for the teachers to challenge the kids. Basically there is a work period and once a student completes their work they have free time to do something else. Free time is the incentive. During free time they can read, do little chores, build with blocks, color, or have a snack. Some of these choices are distracting so they want all the kids to finish around the same time. If one kid finishes in fifteen minutes they deal with a "free agent" roaming the room. DS5 was doing a lot of this until they adjusted his assignments. Now he has to work as hard and for as long as everyone else.
