I have set the locations in our stake center. We had to add the multipurpose room.
After saving I tried to create an event and select the multipurpose room as the location however it is not located in the dropdown list.
I have also tried to check and uncheck rooms from the default list and it doesn't make a difference when the location list appears when you create or edit an event.
Shouldn't what you do in the settings appear when you work with the calendar?
I have tested this with multiple computers and browsers.