I'm thinking of the force placed on the edge of the glass itself by applying it via the inside channel. Placing it around the outside channel allows you to spot solder it in the channel..and if you like you can close the leaves over it and solder along the seam thereby encasing the wire in it's own closed channel.
LoL...I just added to my last post...
It also could mean that the wire, as the diagram says, sits in the outer channel, and the ends of the wire are soldered at 10 o'clock & 2:00 o'clock and the outer leaves of the H-came are left alone...as is.