The child is not sitting on anything so they are lower, the laptop is made of foam not hard plastic, it its curved to go around the child and it is higher on a child than a sheild seat so their upper body is held back. Even my daughter who is 48 inches (max height is 51 inches) can barely lean forward in it.
I hope that makes more sense. Maybe someone else will explain it better. I should mention I have not actually used it. It just doesn't seem right. LOL Its my friends, I just borrowed it for pictures. I was going to use it with my son today in her car but he hated it so we used his roundabout instead. LOL Oh and she hasn't used it either. LOL I guess if I needed it I wouild use it. But with the Regent, Parkway, Turbo, Roundabout and Maxi Cosi with only two kids, the chance of me "needing" it is pretty slim. LOL Oh and I do have shoulder belts in all 7 seating positions. I might use it for feild trips though, its better than no booster!