It's only the display which is wrong. Internally it works correctly.
Ahhh... this knowledge would have saved me hours/days/weeks trying to get the display to work correctly! I had always thought this scenario meant the OS was not handling the newer drives properly. And it did seem as if when writing to the HD (past the ranges that are incorrectly displayed), something would muck up, but perhaps that's another issue altogether. As always, thanks for the expertise and education Thomas!