In the cruise or higher speed range that I describe with the DC3 and Heron ( and I expect most other types) of course, when the engine quits due to fuel starvation or because some mug has hit the magneto master, there will be a MOMENTARY fluctuation downwards in RPM while the CSU makes a correction, but then the indications will be as I describe. Also, although the theory may say otherwise, the throttle needs to be retarded before re-introducing fuel/ignition. Because the pitch has fined off during the power loss, a gob-full of power would cause a momentary overspeed until the CSU gets ahold of it and coarsens the pitch to restore RPM to where it was at the time of the power loss. No theory - simple fact.