My instinct is that each mental state only happens once. If you redo the calculations, he doesn't experience it twice. It's similar to the idea that doubling the size of each neuron doesn't seem like it would change anything.

On the other hand, the Born rule suggests that the universes involved having twice the value makes them four times as likely to be experienced. That suggests that running a one-second calculation ten times would be ten times worse than just running a ten-second calculation.

In any case, I would definitely say that C isn't as bad as A. Moving written values around is not the same as running calculations.