Old Skool,
Actually, if you're flying the S76C+/C++ in 2 cue it will use a cyclic pitch cue to maintain altitude. It's only if you're flying 3 cue e.g with ALT, AS and HDG engaged it will use collective pitch to maintain altitude and then once the limits of the SPZ 7600 are reached, you will get an AP warning as collective pitch is disconnected. Thus RRPM will be unaffected.