[lvr123]

Then you can consider unchecking the "Create Subdirectory per Song" option. That should get you what you need.

I just tested this approach thoughtfully.

And actually, this requires to have unique filenames (you mentioned it). 
So the original filenames must get some discriminant to make them unique.
Those filenames become the song titles, therefore, including the discriminant :-(

So all the songs must be edited manually to clean-up their title from the discriminant.

Passed that point, I can modify the files, re-run the Bulk Import, and there are no duplicates. This is a good point. But the fact that I must modify all the song titles manually make this approach less convenient.

I'll be waiting that a "Parse filename" feature be ever implemented.