Well, those are good questions, but that isn't what is important in this context.
What is important is whether or not -- if we are in a simulation -- whatever is responsible for our consciousness can be simulated another level down.
Now, I already asked Robin this question -- is there any mathematical reason why not?
I am not aware of one, so I will assume that yes, if we are in a simulation, then we could simulate everything in this simulation within a simulation of our own.
And since we have no way to determine whether or not we are in a simulation... any model should take into account both possibilities.
Guess what -- the computational model does. It works just fine regardless.
Do the others?