Responding to this because I just saw a very similar discussion in a new thread. (And I wanted to pop this thread back up. It's useful!)
This does make me curious, since it would be a way to tell the DHD "I'm finished dialing." But what does that mean when you use the eighth and ninth chevrons? (I didn't watch SGU, sorry.) Dialing a point other than your location for the seventh chevron dials "long distance". Now I don't remember, was the eighth the PoO at that point?