This is near-universal in upper flipper games. Let the flipper button out slowly--the upper flipper will drop before the lower one does. The degree to which that's true depends on how the switches are adjusted.
If the flippers drop in the other order, the game is wired wrong.
Learn how to hold the button in this zone, and you're off to the races. Various tricks can make this easier, including using other fingers as a guide, but fiddle around with it yourself to get a feel.