Interesting, thanks.
I tried my battery powered atty on my pass
through and visa versa, and couldn't see or feel any difference at all between the two....
So next I measured the voltage on the battery and got 3.8v and on the pass
through I got 4.1v (If you try this, tape the positive probe leaving only the very tip exposed to help ensure you don't cause a short) Based on these readings the pass
through should be slightly better, but I can't tell any difference at all.