I've been researching old Seattle movie theater ads, and have found that the last two "official" OLGA films were given alternate titles for local theater ads.

OLGA'S HOUSE OF SHAME was called OLGA'S HOUSE OF TERROR in Seattle.

MME. OLGA'S MASSAGE PARLOR was entitled OLGA'S BACK IN TOWN, a rather wimpy title I'd say. The Seattle engagement (May of 1965) was about two months earlier than the usually-reported July opening for the film. Perhaps that engagement was an early test-run. Actually, the Olga character does not appear in MME. OLGA'S MASSAGE PARLOR, so the alternate title OLGA'S BACK IN TOWN must have been quite deceiving to grindhouse denizens of the day.

I do not consider the later OLGA'S DANCE HALL GIRLS to be an official OLGA title. It had no involvement with George Weiss, Joseph Mawra, or Audrey Campbell (or even with the actress who took over for Olga in MME. OLGA'S MASSAGE PARLOR).