The absolute mapping accuracy is really dependent on your workflow and tools. If you have a good static calibration for your P4 camera then you can turn off autocalibrate in your workflow. Next you have to be able to define the accuracy (or weighting) to be used for the positions (photoscan and Pix4D can, ODM can currently not)
The ‘journey’ is outlined here:
I have both good and poor results as I now move into optimising workflows for the improved precision.
I can say that the method massively reduces the need for numerous GCP’s and you can probably 10cm confirmed accuracy with 3 gcps, altitude is massively improved. I am working through various demo datasets that I have collected over time, watch this space.