C of G - Perf 2 is a cross between Perf 3 and Perf 1. You start off as 3 until you reach the point at which you can maintain Perf 1 conditions. The difference between the two is the exposure time which statistically figured to be OK in terms of engine failure. It was created to allow older helicopters such as the 212 to operate until the new stuff comes in.
If you could fly the profile in the first place you wouldn't need it!
Phil