Sorry, I wasn't clear about it. I do mean brass that has gone through both sizing operations.
I've been meaning to do this myself but as you stated, I haven't seen a need to go further than just the Collet die since it works so well by itself. However, I am still very curious about it.
I have a RCBS FL die but the decapping pin broke on exactly the third piece of brass I ran through it. I was so PO'ed that I took it off the press and have not put it back on. I guess it's time to do so!