Non complex dents should in theory be the most straightforward to repair. They would include the door "ding" e.g. where car door meets car door, shopping trolley damage and various other light impacts. They would generally be fairly round in shape and not particularly deep or sharp but still visible when caught in a reflection and tend to spoil what is an otherwise lovely clean, straight car.
The reason for there being such a wide variance in the price is predominantly due to the work that may be involved in gaining access behind the damage. Unforeseen obstructions such as crash-bars, strengthening sections or even sound deadening material will require a different approach to getting the perfect repair.
Apart from being more severe than non-complex damage, there will be more defined and creased or unusual shapes within the dent. Often located around body lines, this more complex damage will be deeper/ larger/ sharper and have some 'bulged out' high areas, these high areas will require far more working from the outside of the panel in order to de-stress the metal prior to and during the application of a series of lifts using multi textured rods or levers from behind the damage. They will require a more experienced technician, higher levels of skill, extensive tooling and last but not least... more TIME to ensure the high quality paintless dent repair result we always aim to achieve.
Special projects can result from varying scenarios such as damage caused by a garage door closing prematurely onto a roof or bonnet, the car being kicked or a bit of careless reversing. Special projects can often involve multiple panel repairs, for example, the car has been vandalised by someone running over it or the car is caught in a hailstorm and peppered with hundreds of dents. Paintless dent repair and rectification of this type of damage requires the highest skill levels combined with cutting edge tooling and technology and can take many hours if not days.