You can't meditate while falling, and once in rock body, you wouldn't be in a position to fall unless some type of plot affect occured. Even then I'd say the ground falling out that supported you definitely broke your concentration.
The previous ruling stands, you would need multiple uses of "feather body" to fall safely. Coincidentally, there is a max of 5 uses.
In service to Kormyre,
Lord Alexander Renaudierre of Frostguard
~~~
Roy S.