I haven't seen this before, but THIS makes sense. I have been working on extensive analysis of my Bally Bon Voyage, going through every single piece of the schematic and figuring it out. I will have a write-up on it, but sometime later when I get time. But as of now I have about 90% of it in my head as far as understanding how it all works. I think the Gottlieb and Bally schematics are similar in many ways.

Anyway, I sorted through the whole schematic and agreed that it was shown in a state which would be after a game was started, then shut off with the ball ready to shoot (which I had read somewhere else). What drove me bonkers was that the power switch was shown closed, and this created an impossible situation because of the position of the game over relay (I won't go into all the details why here, unless you want to hear it). But, if you simply unplug the machine - now that makes sense. The power switch could be closed and this would be an accurate state.

On my schematic, it isn't perfectly consistent throughout as far as the shown state, although pretty close overall as far as I can tell. For example, the Ball Count Unit Disc is drawn with 1 ball to play, and if the game was just started and then shut off, it should be 5 balls left to play (because the jumper is drawn in the 5 balls per game position, not 3).

Yes, this is correct, and BV is an add-a-ball Definitely shows balls left to play.

Edit - a bit more - at the beginning of the game during reset, the ball count unit is reset to 0, then stepped up to either 3 or 5 depending on the position of the adjustment plug. It has a max of 9 for additional balls that can be won during play.