This is, apparently, a bug or at least a deficiency in the tool.
NIM101212: The Pivot Table geoprocessing tool displays zeros (0) instead of 'Null' in the output table for no data values even after exporting the table to a geodatabase table or a stand alone database table.
An enhancement has been requested. I've made a python script tool to find cells that should have false zeros and set them to null.
Thanks to all who participated in this discussion.
Randy
