Screenshots did not make any sense.
What I wanted to know is "mechanism".
In particular, in the case of "Allow vertical warp", the function of "warping" in the vertical direction.
If you use it in the topography, I imagine "overhang" as expected, but the result is different.
Also, if you turn on "Allow vertical warp" on the surface, it does not affect, but when combined with "Less warp at feature scale" different effects will appear.
The more you experiment with Terragen, the harder it is to understand.
I'm sorry not to speak ENGLISH fluently :S