I did this a week or two ago.

While you are importing the file into Outlook, there is a step that allows you to map which field in the csv file corresponds to which field in Outlook. I discovered that I needed to use that mapping tool--the "default" mapping was not good.

Meeting end times did not import properly. I modified the csv file to include meeting end times--obviously, before importing it into Outlook, then that worked as well.

I think (do not know) that you might be able to set the default meeting length in Outlook before importing this csv file, and it might use the default length to calculate the end times.