Box Office Poison was originally serialized in comic book form from 1996-2000 by Antarctic Press. Behold the covers of the long forgotten series:
No, you aren't adding wrong: #19 had two covers.
At right:
Sherman's March: The Complete Box Office Poison Vol 1
, which collected issues #0-4.
Below: some covers from the xeroxed mini-comics in which the story first appeared.