The steeper the angle of the tappet, the faster it allows the nozzle to move forward.
The chip delays that forward movement of the nozzle.
You can look at the tappet another way.
The total time the blade of the tappet is being pushed by the sector gear is roughly equivalent to the time the feed tube stays open during the shot cycle. The shape determines whether it closes smoothly, in stages or suddenly.
Moving the pin on the sector gear may change the point in the piston retraction when the feed tube opens and closes but not how long it remains open for.
Moving it also increases the risk of the nozzle not fully sealing before the piston is released, which is inadvisable.
That will only occur using a tappet with different blade, a delay chip, a different motor or a different gear ratio.
The fun really starts when you play with DSGs.