When I tested it in XLv.X - the add-in type was not available if the
macro sheet was active, but it was available if a worksheet was active.

In article ,
Tom McGuinness wrote:

Upon opening a new BLANK workbook, the "save as" dialogue box
provides ability to save file as an Excel Add-in file. So far, so
good. However, once I've pasted the updated macros into a macrosheet
in that workbook, the "Save as Add-in file" option disappears from
the file format list. I can manually add a ".xla" suffix to the
filename, but it does not create a vadid add-in.

Same things happens with Excel 98, so maybe I'm doing something wrong.