A Hollywood production often involves a huge number of distinct business entities in a complicated network of relationships with each other. Oftentimes, a specific business entity is set up to coordinate a single production, and that is the entity that reports the profit/loss for the entire project -- the project's revenues can be spread across lots of other entities, while its expenses are concentrated in that central entity, producing a nominal loss in their accounting records even if the movie as a whole was extremely profitable.
Production doesn't include advertising or distribution. Advertising can often equal production costs. And box office revenue gets distributed to several groups, not just going to the people who own the movie.
Presumably there's a fair amount of additional costs involved in marketing and distribution that aren't accounted for in the production figures and this ends up being a good baseline for a fuller accounting based on industry trends.
