This is the question I have been asked most in person, and I want to be careful about answering it in general terms, because the honest answer is that it depends on the room rather than on the machine.
The physics of it: a room loses the cooling you put into it at a rate set by how well it is insulated, how much glass it has and how hot it is outside. A well sealed room holds it for hours. A loft bedroom under a warm roof does not.
So the two cases are genuinely different, and the way to settle it for your own house is to try both on two similar nights and read the meter rather than trust anybody's rule of thumb.
The running cost calculator will tell you what each pattern costs once you know the hours. What it cannot tell you is how fast your particular room warms back up.
If anybody has actually measured this in their own house, that is worth more than the theory.