inception - Why aren't the characters floating two levels down?

It is slightly odd, because other senses appear to be able to penetrate more than one layer, although they are severely attenuated.

For example, when they are in Level 2 - someone says "did you feel that, was that turbulence on the plane" (which is Level 0), to which Eames says "no, too close, Yusuf's driving probably". He doesn't say - "of course not, you wouldn't feel anything down here, must be Yusuf's driving". Then there is the Edith Piaf song used to synchronize the kick. That is played by Yusuf into Arthur's ears in Level 1, yet is heard (faintly) in Level 3. Then there is the 'second kick' that they experience when the van hits the water, this is felt in Level 3 - showing that something should be felt of the free-fall even at that layer.

If senses are attenuated with each layer it would be more realistic to think that somewhat less than free-fall would be experienced in Level 2, and some effect would be experienced in Level 3. There is too much discrepancy between the total free-fall experienced by Arthur, and the apparent normality of skiing down a mountain that the team experience in Level 3.

Still doesn't spoil my enjoyment of it though.