Unlike with Hilton this isn't a benefit of the WOH program, not even for Globalist.

If the rate structure of the hotel allows a second guest FOC then they'll usually add it. If the rate changes as it is often the case in Asia then most likely you'll be charged.

That being said I never understood the urge of people being hell bent to register all guests. I usually don't bother to register the second person unless we arrive at the same time or local law requires it (Russia, China). Never had an issue. YMMV