I haven't gone through the B-a-P yet, but might have some info that will help.
The "Player Step Up" energizes from Score Motor switch 5B (N.O. normally open),
A set of switches in the 1st Coin Relay (N.C. normally closed), and a set of switches
in the Ball Count Relay (N.O.).
The "Ball Count Relay" energizes from a set of switches in the Game Complete Trip Relay
(N.C.), and the Ball Count Rollover switch (I'm sure in the ball return trough).
Once the Ball Count Relay energizes, it remains energized from a N.O. set of switches in
the Ball Count Relay, and a N.C. set of switches in the Score Motor 6A