Perhaps the reset they are talking about is the reprogramming of height within the 4wheel airs suspension control module (4WAS Module). Its essentially the suspension brain. It is possible you didn't need to change the compressor. Sometimes resetting the height configurations on the 4WAS Module is all that is necessary. Of course the dealer won't tell you that.
Here is some information from the shop manual:
4-Wheel Air Suspension (4WAS) Module
NOTE: The 4WAS module must receive a ride height adjustment calibration and must pass a pneumatic test
when it is installed new or swapped.
The 4-wheel air suspension (4WAS) module controls the air compressor motor (through an
electromechanical or solid state relay), all air spring solenoids, and provides power to front and rear height
sensors. The 4WAS module also controls vehicle height adjustments by monitoring the three height sensors
and other universal bus protocol (UBP) signals. The 4WAS module conducts all fail-safe and diagnostic
strategies, and contains self-test and communication software for testing the vehicle and related
The 4WAS module monitors and controls the air suspension system through a 26-pin, two-way connector.
The 4WAS module is keyed so that it cannot be plugged into an incorrect harness. There are two harness
Hope it helps.