Look carefully at the picture below. Notice the little black bands on the auger shaft between the blades? Also notice there are no bars on the end supporting the blades?
Apparently MTD decided at some time, I'm not sure when, to use individual auger blades. Each blade mounts on its on section of the shaft and is held by its on shear pin. Now it gets fun.
On the 28" there are 4 auger blades and they are separated from each other. On the 26" the edges are right next to each other. On the 24" they overlap. The 30" have 6 auger blades and they really overlap.
Now say one section snags a rock or other obstruction and jams. It shear pin breaks; so far all is good. On the 28" that is fine. On the 30", as the remaining blades turn the one or two adjoining blades overlap the edge of the fixed bladed and continue turning, the blades grinding into each other, the paint grinding away, until the other shear pins also break.
How long has MTD been doing this? Is this an accurate description or did I miss something? I tried it the store, removing the shear pin, and the blades definitely run hard into each other.