It makes perfect sense to me. A fellow rider who used to dig graves (by hand no less) used to wonder the same thing. That is, until I asked him why he got cement in the 40 lb. bags instead of the 80 lb. bags. He said it was easier to unload them and carry them to the mixer. I pointed out that he had to make more trips that way, and he responded, "Yeah, but the trips are easier and I can do them quicker." Then his eyes lit up and he said, "Oh, yeah, that makes sense. When I'm in the big ring it's like carrying the bigger bags."