The Outlook add-in currently by default displays the US number for audio callers.
eg. Join as an audio only caller:
US: +1(512)489-3100 extension ######
International numbers: https://manage.lifesizecloud.com/#/numbers
It would be better if there is a setting to change the default to another country. Alternatively make the Outlook add-in look at the country setting of user profiles to determine the appropriate number.
The same applies when creating meetings via the Lifesize Cloud program. It also defaults to the US number.