looking at the ratchet side of the unit ...
the step-up pawl's job is to push the ratchet one tooth clockwise.
the reset pawl's job is to prevent the ratchet moving (much) in the counter-clockwise direction when the step-up plunger is pulling in.
if the black escapement pawl is not there, when the reset plunger pulls into the coil, both the reset and step-up pawls are lifted off the ratchet teeth and the torsion spring on the ratchet causes the ratchet to whizz counter-clockwise back to the reset stop/zero position quickly.
when you want the unit to step down instead of resetting completely, you toss on the escapement pawl. Its job is to grab a tooth when the reset plunger pulls in and acts like a second reset pawl.
it's normal for the escapement pawl to be floating above the teeth until the reset plunger pulls in. It needs to let one tooth get past it when the plunger is pulling in or the ratchet won't decrement.
between the escapement pawl and the reset pawl, the ratchet can only spin one tooth counter-clockwise instead of spinning all the way to the reset stop (google for "clock escapement")
you won't see the behavior of the escapement pawl if you are pushing in the reset plunger when the unit is already reset. You need to step up the unit then push in/release the reset plunger to see how the escapement pawl works.
if your problem is the unit is getting to zero/reset position but the reset plunger is still pulsing (bonus scoring didn't finish), check the switches the white peg on the ratchet is pushing. Usually one of them ends the bonus scoring.
unfortunately, my trio schem is nearly as bad as the one on ipdb. If you have a good one and can take highest possible resolution pictures of it (overlap the pics ... too many is fine), please email them to [email protected] and I'll use them to fix what I have and get it onto ipdb.