That is only if you always watch your movie start to finish. If you don't consume the whole film that number goes up dramatically, say if you watched 5 minutes

That is only if you always watch your movie start to finish. If you don't consume the whole film that number goes up dramatically, say if you watched 5 minutes at a 5MB/1MB connection, then you could download 1.5GB (probably half the movie) while only seeding 300MB back.