"1. The optimum Nr for rotor performance is 100% (any more or less and the rotor is LESS efficient)
It depends what is your flight condition or flight profile. For Cat A operations optimum NR is 102% as pubblished
2. In order to meet the RFM Cat A performance standards, any OEI flight during take off and landing must be conducted with the remaining engine at maximum power.
In order to meet the RFM Cat A performance you have to stick to RFM procedures that are quite clear. FADEC will take care of the power once you take care of the pubblished procedures
3. To ensure that this is so, the collective lever must be raised until the Nr droops. This will bring the remaining engine up to maximum power. If the remaining engine is NOT at maximum power then the performance promised in the RFM cannot be guaranteed.
Not true, collective has to be kept at the same position of a standard AEO maneuvre unless a droop is necessary to achieve transational lift to accelerate to Vtoss
4. If the starting point was 100% Nr then this would mean that when the Nr was 'drooped' to say 98% then the rotor was working at a less efficient speed so the Nr is set to 102%. Thus, when the Nr is drooped it will droop to 100% where it should remain until Vtoss is achieved.
The starting point for Cat A can only be 102%. The droop is allowed up to 90% and is not meant to achieve a better efficiency but to convert the huge M/R inertia into transational lift, once you have achieved Vtoss you have to recover your 102% NR setting.
100% Nr is only for Cat B because there is no need for extra power to ensure best Cat B performance in the entire envelope.