Not sure why people don't get this, yet. Studios DO NOT see 100% of the box office revenue. They only see about 55% when all is said and done. The production budget also does not usually include the marketing budget. And for a film like this, with as hard as they have been pushing it, is easily $200M, if not more.
You see WB is desperate to get a DC cinematic universe off the ground that is just as successful as the Marvel one, so they are spending just as much as Disney is, if not more, to make and promote these films. Problem is they come off rushed and lack the same respect Marvel shows their characters. So, even though their movies are opening big, they have nowhere near the legs of the Marvel films. That's why Civil War made over $1.15B and is a big hit, but BvS couldn't hit $900M and is a disappointment. Personally, I see the same happening with SS, but we'll see.