I have seen the same thing I think, are you doing a quick defrag or a regular defrag. Cuz if you are doing a regular defrag you could have 0 files to defrag and it will still look like it is defragging other files. I am guessing the reason they did that is because when you do a full defrag you all so are defragging Free space. But I agree with you why not be specific on what it is doing.
John