Interesting topic, but it is a bit too late to write much. One point to make is that the accelerate stop distance depicted in the profile is a function of speed at TDP, and not weight ( for all intents and puposes). This means that it is (as said elsewhere) the profile that remains constant, not the absolute power applied. If you are light then you simply apply less power than if heavy. With the same attitudes you should end up at TDP more or less in the same point in space as you would at MTOW using MTOP (or what ever you need for that circumstance).
The weight penalties imposed by lower TDPs (CDPs) on a/c such as the 76 A++ are not a function of the rejected take off space being lower, per se, but of the lower Vtoss that the lower TDP dictates. Obviously lower TDP means lower Vtoss as you have to attain Vtoss within the Cat A requirements, and so (eg) with a 35 kts TDP you can't expect to reach 65 Kts Vtoss before hitting the ground (let alone clearing 35 ft obstacles). You might reach 45 kts though, and this speed with its attendent climb rate dicates the weight, not the distance required to stop.
As an example of the distance vs speed rule, the EC-155 reject distances for varying TDP are the same as the AS332 L-2 for the same speeds, despite the weights being 4,800 kg vs 11,200 kg respectively.
I also agree with the remark about fixating numbers to the extent that the pilot should be able to feel and visualise the procedure by external reference, but only if that is accurate enough to produce the desired figures and therefore meet the required result.