Your assumption is very much correct on the metered thing, you will need Xerox to either convert the machine, or you will need to replace the toners. It is not free, Xerox charges for conversions.
Immediate overwrite is simply done. It is nothing to be concerned about.
CWIS > Properties > Security > Image Overwrite Security > On Demand image Overwrite > Start
To explain the Overwrite error: <In a clear way that is not by any means using Xerox official language>
The printer is set to immediately wipe any data as soon as it is no longer required. So it scans a page, converts it to pdf and emails it out, it then wipes all data associated with that scan so that it cannot be recovered by someone even if they pull the HDD, Decrypt it and try and restore it.
But, the machine isn't stunningly bright ;-) , Occasionally, it sees data that needs to be deleted/formatted, and it does so, but while it is doing it, someone does another job (print/copy/fax/scan) and that jobs data is there after the wipe. So the machine incorrectly thinks that it failed to overwrite the data and displays the error prompting you so you know there may be something there, and to run it again manually.
