Look - there are about 10 work groups that work to get the flight out. When there is a mx problem the pilots call mx control and mx control dispatches the mechanics. There is no interaction between the pilots and mechanics until they arrive at the airplane. How in the world does anyone expect the pilots to be able to pinpoint with swiss timing, the amount of minutes it will take to deal with a mx problem? When you take your car in for repairs, they give you an estimated time. There is no difference here. Mechanics get a BASIC idea of the problem when dispatched by mx control. It isn't until they arrive at an airplane and do their job, that the whole picture is discovered. THAT is why most delays are "rolling." We're also required to update every 15 minutes, with or without news, so that you're all kept in the loop, which is where your dreaded creeping 15 minute announcements come from. Sometimes we don't have the whole story or an accurate story to tell you. Passengers just have to have patience and flexibility when something irregular occurs.