>>They have different extensions and since the SaveAs() method is invoked instead of Save(), the extension will be qualified by excel - I think.
>
>I think, if you don't specify a type with additional parameter in SaveAs, it'll be saved as is w/o converting to XLS. IOW, specifying XLS extension doesn't convert open document to XLS type.

Hmm. Not sure about this. It did save the file as a regular excel file.