I've written something to do this in the dashboard as a userModule component, but it'd probably be labourious doing it for each point...
But it allowed me to export all of the data from now till some time prior and generate a CSV that I could use to import the data with the new XID. However it still meant mapping the current point name with the new point name...
If that interests you, let me know.
Might be good to tweak it to automate it further for future ease of use....
Fox