i believe they are the same length, shelf might have to do with trap size and trailer heights. they dont have a crank to stick out but the bottom of the hopper is wider and the hydraulic cylinders sit beside the hopper opening yet, its definitely noticeable when trying to get the swing auger to hit both hoppers without moving semis. the lag can be the difference between plugging an auger or not, so not trivial to me. the buttons on the hopper have less lag in the remote but if i wanted to stand beside the trailer in the dust i could use a hand crank then