The cost of the open sleeper ticket has gone up significantly in the past six months. Previously it was the same as a coach fare, but now it is much higher. I recently added my wife to a ticket from Cincinnati to Glenwood Springs. The coach fare was $154, but the open fare ticket was $100 higher. You can determine the cost by comparing the sleeper fare of 1 person vs 2 people. I think Amtrak is trying to capture the additional cost for the meals for the 2nd passenger. Sleeper costs have also gone up dramatically in the past 6 months, especially for bedrooms.