We frequently get asked this question, so we confirmed with the State Geodetic Advisor of Wisconsin, John T. Ellingson PE PLS , NOAA’s National Geodetic Survey (NGS.) http://www.ngs.noaa.gov
“If you extract datasheets from this point on, you will notice that the published GEOID HEIGHT will be listed as developed through GEOID12B, rather than the previous GEOID12A. Do not be concerned about this, as both models are exactly the same for Wisconsin. Here is the note that the NGS Geoid Team provided to us concerning the new model.
“NGS has produced a new geoid model, GEOID12B, to replace the previous GEOID12A model. GEOID12B is identical to GEOID12A everywhere, except in Puerto Rico and the Virgin Islands, and it supersedes models GEOID12 and GEOID12A.”
Note: Views expressed are those of the author and not necessarily those of NGS or WisDOT