No, was just thinking of possible leaks storage side. I was skimming the posts and was a little uncertain if it really is losing air and dropping at night or just self-levelling.
Depends if it is on a slope. If a corner goes beyond a certain threshold it will try to self-level. Early cars seem to do it a lot more than later ones. Calibrating the suspension may help if a sensor is borderline. When you remove the delay-timer it takes all that nonsense out of the equation. If it isn't dropping with the delay timer removed but the pump is running a lot then either there is a leak storage side (there are some NRVs in addition to the little black o-rings required to completely overhaul the valve block) or there is an electrical fault of some sort causing it to run. Dancing at lights has been mentioned before but it might be the connectors to the driver-pack itself inside the EAS box - the flat black thing.