I'm grinding for 60 BP and finding it very slow. The upgrades that put BP on the field and in the cups seem intermittent. Sometimes I hit the BP in the cups but still only get 1 when I finish the level :/ Is there some extra thing I have to do for it to count?
EDIT: it seems like
* the ones in the field just don't do anything
* if I beat a new level, I only get 1 even if there were any in the cups
* if I beat an old level, I get the ones from the cups
And once the timer is zero, even if a ball is still bouncing around and lands in a cup with a BP in it, I don't get that BP.