Mike's law of movie multiplication

I saw Mission: Impossible III at the matinee yesterday. I was disappointed that the movie's music was not in 10/8 time like the TV show's music.

Did I ever explain "Mike's Law of Movie Multiplication"? It works as follows. Going to a movie alone costs X dollars and gives Y units of pleasure. Going to a movie with a date costs 2X dollars and gives 2Y units of pleasure. Since the single-o can attend twice as many movies, the total amount of pleasure is the same.

This Law doesn't hold if each person pays for their own ticket, though. Or if the other person pays for both tickets. Or...