that repairing even small dents can be very labor intensive. For example, to repair a small ding about the size of a dime can require that you sand an area the size of a salad plate. Moreover, if you need to repaint, you need to repaint the entire affected area to a break line (a hard bend in the sheet metal or to the end of a panel) in order to make sure you cannot tell any difference in the paint.
If this scratch is deep enough to require any filling and it affects a couple of panels on the body (like the rear quarter panel and then the door), and those need to be repainted, suddenly $900 seems not so high.
