When you do a full XML export, yes the AO table object are exported as XML in the
entities.xml. However I wouldn’t recommend using this because it doesn’t respect any context you may have with the export (e.g. it exports all data, every time ignoring chosen projects or users).
It would be better to make sure your export is context aware with the projects (containers) selected. Depending on your data, you can add a timestamp to each export so the second export may only requires newly updated content - however, this is very dependent on your app and data model.