Yep. I think I got the wrong number flipping between tabs - I was comparing to various movies, and probably grabbed the budget from the wrong one. My apologies.
The unit ticket sales I worked out hold, however.
Also, I don't think its fair to hold Ghostbusters to the standard of movies that came after it. Executives at the time wouldn't be aware of those figures. I think checking out '83 and '82 movies would be a better idea.
It's mentioned that before Ghostbusters, the highest grossing comedy movie was 1982's Tootsie. Tootsie had a budget of 21 million and a gross of 177,2 million and was number 2 of its year. That ends up being roughly a 8 times return on investment, slightly less than Ghostbusters. No 1 of '82 was E.T. and THAT was a hugh hit with other 35 times its return on investment so that might be the kind of things Execs would look at.
Return of the Jedi, the previous year, was no 1 movie and had a return, domestically anyway, of only 6 times its budget. Though it was a third sequel in an established franchise. No 2 of that year was Terms of Endearment which also had a return in the 10 fold range.
So I can see them considering Ghostbusters a hit, but I also see them think it was not enough of one to consider a sequel until five years later after the brand established itself in other markets. Hollywood was different at the time.