That's not a LLD issue, that's an aircraft Ai issue. Waypoints are designed for humans. The activation area is very small. The A10 gets distracted, and those little distractions will make it completely miss its waypoints. It then has to circle around. But it circles slower than the AI thinks it should, so it ends up loitering in the target area.
It does this even worse in MP. What you need to do is slave it to a given flight path, (point it in a straight direction, give it a waypoint onthe other side of the map, set it to careless/never fire, and use triggers to set "open fire" as it approaches the target area), and hope it works.