There is a count of vertices which in turns tell the vehicle when that specific fence polygon is done upload. If there are four vertices then there should be four mission items in a row.

Ok I was wondering was that first parameter meant. So if there are eight points and each of the points have 8 as that param, the autopilot will interpret it at one big polygon. If all of the points have 4 as that param then the autopilot will interpret it as two polys of size 4