It took a few weeks but I did get a response regarding the Kumho 857's,
from the Kumho tire engineer:

"Sorry for the delay getting back to you, but I wanted to hunt down the
reason for the wording of our ad copy. Basically, the copy is a bad
translation and this tire does not get any attention from the marketing
guys. The bottom line is that it should be an excellent choice for the
Westy.
Fran"

So, looks like Tire Rack's info is incorrect! Good to know that there is
indeed another good tire choice.

Karl