Thanks!

I opened the original spreadsheet used to build the .XLA;
then clicked-off the addin;
in the VB editor, updated the XYZ7 function name to lowercase "xyz7";
filed it down and entered XYZ7 into a cell ... result = "xyz7".
Re-opened the VB Editor; changed "xyz7" function name back to "XYZ7".
Filed the macro. In the cell, "xyz7" entered and ... result = "XYZ7".