Avatar's opening weekend was estimated at $73M and using the standard 2.7 multiplier, it was adjusted to $197.10. A film only has one opening weekend, and only adjusts once. Only the box office total for its opening weekend plus the following three weeks are used in pricing a moviestock. Yes, on Avatars most recent weekend, it made $16.2 Million, but this is not important for playing hsx as the avatar stock has long since delisted.
You can check the hsx box office page for official numbers. it is located in the menu bar under "on the exchange"
You really need to read the help section and the players board to help you understand this game.