With the magnet activated that should be a 100% shot all the time. The problem I had with mine at one time was the magnet post had a groove worn into it. I took it out and smoothed off the groove. Readjusted to the proper height and I was making that shot once again everytime. Rebuilding the upper flipper might be needed too as that flipper coil strength isnt' the strongest since it is such a close shot. Just throwin ideas out there.

If i remember right that magnet post is threaded. Just adjust the height a tiny bit for starters to see if that helps.