Course backups not automatically being removed.

I am using moodle 2.3.  In my automatic course backup setting,  I set the Keep number to 2.  The text beneath the Keep settings says

"How many recent backups for each course do you want to keep? (older ones will be deleted automatically)"

I interpret this to mean that moodle will automatically delete course backups when new ones are created, in my case once the 3rd backup is created, it will delete the 1st.  I am saving the backup files to a specified location other than the default.

There are currently 7 copies of each course saved.

Am I interpreting this wrong?

Thanks