What's surprised me is that article has dropped a billion...

What's surprised me is that article has dropped a billion dollars off the earlier 1.5 to 2 billion valuation in a different article.

Impact, which is privately owned and focused on exploration in Africa, has hired investment bank Jefferies to prepare a sale process for its stake in Block 2913B, which is estimated to be worth $500 million to $1 billion, the sources said.

Is that something to do with Total stating its smaller until they drill more wells to confirm the size? Wouldn't be surprised its a case of a major playing games with small players. Seen it all too often.