Maybe I didn't describe it well, but the author indeed was talking about current differential between the body and tail. So, for example, a slightly faster current on the tail could drag the body. But, we're talking about a total length (tail plus body) of less than half inch, so maybe that's splitting hairs.
I like AlanB suggestion of trying it and let the fish judge. Maybe I'll be prepared to snip the tails on a fly in a trico spinner fall situation and see if it makes any difference.