For the record, the SHO *IS* a Taurus. The fourth gen SHO is based on the sixth gen Taurus, but the SHO is a Taurus.
I suppose we could argue about this until kingdom come. But, consider this: the Ford LTD was initially a trim level of the Ford Galaxy, that was eventually spun off into it's own model. So, was the first LTD a Galaxy? Or was it an LTD?
It's really not worth arguing about. I'm just nitpicky, and that's because the first through third generations of the SHO correspond with the lesser Taurus models, but then the SHO skips two generations, and reappears based on the sixth generation Taurus.