Thanks. I get it now. The plans don't seem to show adel clamps but they make sense. And whether it's an adel clamp or a ziptie, having a cut-out to clear them makes sense. I was picturing zipties in the holes in the web of the flap motor channel's aft side (the permanently-riveted-in one), which now that I look at it again wouldn't work without drilling extra holes.
The F-01406B mystery will remain a mystery unless someone else knows why those nutplates are called for. At least I won't feel like the only builder who doesn't know what they're for.