Thats very sensible biz. I think the NADP is flawed both from an aircraft handling perspective and from a noise perspective (as I mentioned, noise and vibration is my previous career and I worked for the company that made buckets of cash out of selling noise monitoring stations to airports amongst other things
Airport environment management - Brüel & Kjær). There's nothing unsafe in either method (actually I think strict adherence to the letter of both NADP1 and 2 has some safety implications for aircraft like ours). I hope you agree that the subject is also worth discussion at some point and not only on here - the rulemakers need to see the arguments against the noise profiles they suggest. The issue with the NAP's is that unless you force operators to remain at full chat you have no way to prove repeat-ability in your noise samples. The maths is just too complicated if you let people do the sensible thing and climb at a high rate in a clean configuration with the power reduced because who knows what noise you make when the throttles are in any position other than max take off. They take the simple option and say "max thrust, known noise source, make the aeroplane climb at the steepest gradient we can" because anything else can't be proved.
anyway, thats another thread..