Quoted from Rokablly:
Got my Premium yesterday and besides the crazy random and consistent air balls I am having issues with the ball not making it out of the subway tunnel. I remember others mentioning this but can't seem to find the fix for it. Any help would be appreciated.
FYI, I have the bubble sitting in the middle of the level but it is right on the bottom line. The game is so fast I was hoping that would slow it down a bit.
Also to add,
Crazy as it sounds, game actually plays better around the 6.8-7 degree range.
(Setting your coil pulse down one notch helps too.)
That will help your subway problem a bit by slowing the ball down enough on the entrance ramp to allow the smooth steady drop it needs to flow back to the flippers and also lessens the angle needed to make it out the other side. Any fast moving ball across the top before it hits the drop into the subway will rattle around causing it to stall in the subway for the eventual ball search scoop kickout.
Besides the pitch correction Rok, GBP needs a bit of extra work on your part to dial in the rest of the PF to make it shoot as smooth as butter.
(Like with what was said above me by arcade/bhwolf.)