Okay I've found a little mistake here. It's not 10 times over. It's "just" three times. And that's just a dull sword, with a masterwork weapon, you can cleave through a bone six times bigger than a human arm's one in one slash.
The penetration values on weapons are so big that a sword sword can (if wielded by somebody very strong and huge) cut off an elephant's leg in one slash. I'm pretty sure that's physically impossible.
Considering dwarf fortress has no such thing as a dull sword, I'm going to assume we mean a low quality sword. A sharpened, but otherwise ordinary, sword should be able to cut through at least 2 human femurs, which is the strongest bone in your body. 3 could very well be possible, but I certainly won't claim it. The humerus isn't a particularly strong bone, so I could imagine cutting through 6 in one swing (not really the same thing as making one giant super bone), although this could too be implausible.
Bone is a peculiar thing, it doesn't cut very well, and its really just the blunt force on a small area that causes very specific breaks, so as we start adding, things behave much more differently and become difficult to predict. The more outlandish scenarios are pretty hard to predict.
However I believe that the right man, with a large two handed sword, could cut through an elephants leg in a single swing. Keep in mind that the macuahuitl could cut through a horses torso. It wasn't really a single swing, there would be sawing action, but for a wooden club with bits of glass on the side, that's impressive. A great sword has a much better cutting edge, and likely even more momentum than the macuahuitl, so it may be up to the task. I assume your calculations were for a dwarven short sword, and that certainly couldn't do the job.
So I'll agree, the numbers are off. But I honestly think some people here have unrealistic beliefs on the limitations of these weapons. That's understandable, we don't usually slice each other up anymore, but think about the forces involved. If a normal sword (granted not a short sword) can cut through two pigs torso's (closest human analog) in a single swing, it has the potential to do some damage. Even without its cutting edge, the sheer momentum involved in a metal club with a small contact area is certainly going to break some bones.