Sure, they are commensurate at some point. I'd pick one nanosecond of torture over the dust-motes, for instance. But I'm not certain that I would ever choose the 50 years of torture over the dust motes for any number of dust-moted people. That's because it's not continuous, so you can't do the sort of epsilon-delta proofs that Yudkowsky's argument depends on.
At least, in my opinion.