It seems that when you overclock a recycler sufficiently, it stops producing any scrap. I just fed mine 2.5 stacks of items and it didn't get a single piece of scrap. That's definitely not a 1/8 return.
I've put 6 overclockers into my recycler to get this effect, but it seems to produce diminished returns when loaded with 4 or 5 overclockers.
My bad. Nevermind~.