3 Top,
The new style B3 with the 2B1 engine is axactly like the B4. Identical powertrain sans a few input differences from the airframe side. This is a good way to identify your actions in the case of a gov issue in flight. Since the new B3 and the 130 are dual channel and totally fly by wire EC installed a thrid back up system called the EBCAU. In the case of a single channel failure you will get nothing as it is considered a loss of redundancy and indicated after shut down. If you lose a signal to the DECU that has no back up then the system switches to a back up law. Basically it assumes a conservative number to replace the actual value that is missing. In this case it gives you the steady amber gov light in flight. This means things will work as advertised but it may be slow to respond or possibly not produce full N1 speed if asked. In this case...keep going but dont try to land on top of Everest!
If you get a dual channel failure you will imediately get the red gov light. This means the stepper motor is frozen in place. The same out put from the DECU that turns on that red light energizes the EBCAU and sets it into motion to govern fuel flow. Once it is activated it send s a signal to the panel to illumintate the amber gov light which is your indication that you are once again flying in the degraded mode. Like you said no abrupt power changes.
If for some reason you get the red gov light and no amber light then you have a problem. At this point nobody is driving and you may be stuck with the power setting you have at the time. I've yet to hear of it happening but be aware of how the system works so you can react appropriately.
Max