I have completed 2 flights over the same location for cut and fill numbers using my P4PRTK connected to the Cors network. When I was comparing both maps together, my Z value was off by -1.80 ft. I was a bit surprised by this. Got them aligned and everything turned out ok. But my question is what if I was just doing one flight of a field to get the elevation of it while using the Cors network. How would I know the accuracy of the Z value?