The machine by default is set to United Kingdom. According to the manual, adjustment A.3 21 Coin Meter Units has to be set to anything but OFF to establish the coin unit for a meter attached to the knocker driver and override use of the knocker during awards. However, on my machine that adjustment is set to OFF so I would expect the use of the knocker to NOT be overridden 
Matthew
OK, so with the new ROM you now have adjustment 3.21? I would still set jumpers 14 to 18 to the USA setting as after this I am out of ideas.
