As shown on the plan the pivot is actually ahead of your layed out 25% mac so all would be well with the original design in that regard. It was your original sketch that got the wolf pack all riled up. The picture of the plan (complete with glue blobs ) shows that the designer wasn't on drugs and all is well. The sweepback working to move the MAC to the rear enough that the pivot is now comfortably in front of safe point.

The hinge point above the surface is still a pretty funky way to do it but it would definetly work. It's just that the surface would sort of rock back and forth a little like an upside down cradle instead of just pivoting. No ills would come of that other than a slight extra servo load. As long as you're using something strong both in output and gear toughness it would be fine with no redesign. In fact since this is for a ducted fan or turbojet I'm guessing it was done like this to keep the linking rods below the outlet pipe or duct.