Maybe because it is producing revenues close to 100 mil. If running effeciently projected to produce 3-5 mil profits per year (might be right now, have not had update in quite a while), put just a low P/E of 20 on that, makes centerline worth $60 to $100 mil. $50 mil, IMO very low conservative number, $60-$100 mil more optomistic realstic number.
Also to take a bit further, many high tech cutting stock are running on a 80-100 P/E, put that with $5 mil profits and your talking $500 mil. top end, a little less than $5 per share.
IMO, $50 mil would be a steal for a solid producting company like Centerline. $80 mil. would seem to be a fair deal.