Are there two forms of resistance in this exercise? I know that you attach a DB or a plate to your belt, but what is the platform in the middle of the V shaped benches for? The author says something about placing a DB or a plate on there.
The author suggests you use the bench to increase the range of motion. If using a dipping belt, 45 plates or even most dumbbells it is very likely that the weight will touch the ground and depending on your goals could be either be a desirable or counter productive effect.
Sounds like you’re referring to John Parillo’s hip belt squat. The platform has a hole in it which allows the weights to descend down under the platform when you squat which gives you a better R.O.M.