Originally Posted by Redcivic47
But my understanding is that load leveling occurs after driving over bumps and then the shocks level themselves against the weight. QL adjusts parked as soon as the weight is applied.
No, they both work the same way for basic leveling. They level the vehicle whenever the sensors see the same reading for a programmed amount of time but do nothing when the suspension is in motion such as going over bumps. (see below for the way QL handles height changes under motion)
For example, when you load the rear while sitting still it will raise the vehicle to the proper height. It will also level when you stop at a light or stop sign if you are stationary for a long enough time. It will lower under the same conditions.
The biggest difference is with the QL where it can change height while in motion. It does that by averaging the readings of the sensors which is why some hear the nitrogen tank "ping" while underway, usually when the system is switching between auto and aero height.
Also note that the load leveling is an open system, meaning it pumps and vents to atmosphere where the QL is closed and recirculates 99% pure nitrogen.