Agreeing with shminux above, elaborating a little... there's a general agreement that marginal utility changes aren't linear with changes in the thing being measured. How much I value a hundred dollars depends on how much money I have; how much I antivalue a minute of torture depends on how long I've already been tortured.

So I expect that very few people here will claim that 1 person getting a million dollars has the same aggregate utility as a million people getting a dollar each, or that 1 person tortured for a year has the same aggregate antiutility as half a million people tortured for a minute.

One reason the Torture vs Dust Specks story uses such huge numbers is to avoid having to worry about that.