Once the cabin has reached "landing elevation" there should be no cabin V/S at all. For instance, if you start descend and then you have to hold for a long time at low altitude, and land after 40 minutes, the cabin will have been at landing elevation for over 15 minutes.
What is the difference between landing with cabin at landing elevation and landing with cabin at landing elevation minus 150 ft?
Differential Pressure, I guess. I would say that is the reason for it. With the cabin lower than the airfield elevation there is some positive differential pressure, which may be desirable for some reason.
Question is: what can that reason be?