I found a few old links with this same question, dating back 2008 or so. Now I had the same question in 2016.
But, as I was writing a post to ask the question, I found the solution, and felt I should share it to others who may want to do the same thing.
What I was trying to do:
I want to ungroup QTY in the BOM. So, if I have two instances of a single file, I want to show as two separate line items.
Solution I stumbled upon:
(This requires that a unique designator, "Component Reference" has been added to each part in the Assy. To do so, in the Assy Tree, RC a component and select Properties. Enter Component Reference: in the appropriate field)