Ralph,
I often do that with "unruly " hackle. The fact remains, that when you tie off the hackle, you really can't help but mash the barbules at your tie off point.
With the method above, when you tie the hackle off, you are doing so on a bare stem with no barbules to trap.
This is especially true when tying a parachute. Tying off a bare stem is much cleaner....I believe.