Ackman's valuation is over three years old and based on old information. His recap scenario involves a 10 year plan before the entities are even released back to shareholders. He also has lost half his clients money in the last three years which is why several are leaving his fund. Highly doubt he stays in business longer than two more years. Most people who go from $19b AUM to $9b rarely stay in business.
The math is easy. All you have to do is think about it.