Difference in rear rating

I have 46,000 lbs rear ends.
The various sizes have heavier components and heavier axle housings.
For example, a standard axle may have a 9.5 mm housing thickness, a super 40 can have an 11 mm thick axle housing and my 46's have a 12.7 mm thick housing. Of course there is a significant weight difference as you go up in capacity.
Some have reported that the thinner housings can flex under heavy loads, causing tire wear.

 

Heavier housings, heavier duty gears inside.

 

I thought everything is heavier.

Heavier axles, heavier gears, heavier bearings, even larger brake shoes.

And everything is more expensive.

 

Id suspect all components larger, thicker, heavier and with more bolts or bigger bolts. Bigger bearings and brakes.

 

My rear is too big.