If memory serves me right, the problem with the C+ when talking about erratic engines was the collective position sensor. They proved to be unreliable and on occasion would send erroneous signals to the DECU so that one engine would run up into blow-away power while the other engine would obviously go the other way. Significant torque splits ensue. If you don't take a wait and see approach, I can see how it would be easy to grab the wrong engine. Every time this happened while I was flying, it was only momentary and a change in collective pitch would restore normal engine operation. However, the Ng changes are rapid enough to really get your attention.