Thanks for swinging by the DroneDeploy Forum. Currently, our elevation values correspond to the relative elevation of the ground to that of your takeoff point. At this time, if you want to change the elevation of your map using MSL elevation, you would have to apply Ground Control Points to your maps. However, our Product team is currently looking into implementing a new tool that allows customers to adjust the elevation values. Although we do not have a firm ETA for this feature yet, I just wanted to let you know that we are already working on addressing those type of feature requests
As for the volume export, I would recommend you using our PDF Annotation Report app. Please give it a try and let us know if that works well for you.