But what are the assumptions of SH&E? All of us have 'assumptions', but they are of no use if they are based on unrealistic or faulty data. Where did they get their data from? For example, I was told that SH&E have their own costing formula for implementing a schedule. The problem is that they did not not consult with financing to see if the rates they used are realistic (things like aircraft maintenance and leasing rates, landing rates, navigation charges, etc...). If this is true, then would you still believe in the numbers of SH&E? I would not bet on that. So one has to be careful here. You can make a presentation and put in all the numbers you like, and unfortunately, most people fall for that. But are the numbers based on accurate and trustworthy data based on realistic and achievable assumptions? That is the million dollar question.