Make sure the two little fingers on the shooter gauge are even. If they are crooked, it will cause to ball to sit unevenly in the shooter lane. They can easily be bent by hand to allow the ball to sit properly. Also bent slightly forward or backward to allow shooter tip to hit harder or softer. The position of the shooter assembly in the cabinet is very critical as others have mentioned.

There are a ton of little adjustments that will add up to a consistent plunge. Even the way your hand grips the shooter handle and releases it. I try to always grab with my index finger and thumb and pull to the correct mark on the shooter guide, then move them at a downward angle so they slip off at the same time. It sounds weird but it works, the 100,000 shot isn't hard once you have everything dialed in.