1991/02/06 Hollywood, CA Stardust Ballroom (Helter Skelter) - This seems to be a spurious 2nd date, maybe due to the VHS circulating? Ask Richard Alan White about what the date on his filming was, and if there were 2 shows.
1991/08/29 Koln, Germany Luxor - Show was solicited, but apparently may have been cancelled. The show has been removed from setlist.fm already. Why?
1994/03/18 Phoenix, AZ The Roxy - <s>Did the second show happen at The Roxy? NIN Historian originally had The Grind. Some guy on setlist.fm also claims it was The Grind, though his anecdote does not actually provide any evidence to back that up. happinessinheresy's newspaper clipping shows both shows were sold for The Roxy, so if it changed, it was a last-minute venue change.</s> [http://nintourhistory.com/uploads/tickets/154422523288image.jpg Ticket stub] confirms 2nd show was at the Roxy.