I've heard this is true, but I can't verify it.
The story went so that serious crossed it to "increase yield" (see original text; "In 2000, Kali Mist was improved for better yields"), while Sag took the original KM/WW and crossed it to a Haze dom male.
"So actually, there isn't pure pre-2000 KM/WW available. There's only two crosses of it, other being the Haze cross and other being the _SUSPECTED_ (no facts available) indica (Afghani) cross.
I don't really know the truth, i just have read that people get better results with KM or in other words it's harder to get good specimens out of WW."