You're wrong. They've had SS houses on a 3 house tour in the past. It all depends on availability because what house you'll actually get to go through can change at any time. It has happened.The SS houses were not normally on the 3 house anyway I believe, correct me if I’m wrong.
I've had SS, (original) Parade Building & Sprung Tent all on the same 3-house tour
With the event starting 3 weeks after these UTH tours start, I'd certainly hope they'd have all the houses more or less "guest ready". Especially since all of August their focus needs to be on food booths & SZs. Not to mention rehearsals & employee previewI can’t see them wanting and having 9 houses out of 10 ready for guest.