One user informed me about the problem with the data exporting from excel to KML file. We identified the problem in local language settings. If user using on his computer the comma as a decimal separator, the KML file is created incorrectly. Interestingly, this setting is also used on some of my test computers but I never had a similar problem.
The problem has been resolved and you can download and install the updated version of GIS.XL 2.0 add-in. If you use a decimal point in your OS, you don’t need an updated version and you can use installed add-in.