and you're right biz but a critical part about the noise abatement departure is ignored. Very few pilots adhere to the speed schedule for NADP claiming that the body angle is too high (and they are right) but climbing with excess power against the drag causes more noise and degrades the climb. Everyone keeps saying that the increased drag is minimal and its not for long etc but ANY increased drag is increased noise and increased footprint. Also, I have never seen charts for climb gradient at speeds above the minimum flap retraction speed so you don't know by how much you have increased the noise and footprint.
This is a good reason to start a proper discussion about noise abatement procedures and come to an agreement with the authorities with regard to noise because at the moment I think very few departures are compliant with the rules.