aviatorhi, take care with your assumptions. The margins discussed in the Boeing document generally relate to time, which translates to distance.
In the diagrams showing V1, none of the options / margins changes the value of V1, which in some applications of ‘calling V1 early’ might happen.
CS 25 AMC section refers to the accuracy of published data; for V1 this is 1.5 kts, or less if it results in a change of 100ft or more in the performance distances.
From limited experience, small speed changes around the value of Vmcg can result in significant changes in the ability to control the lateral deviation, e.g 1 kt below a demonstrated Vmcg at limiting cg, etc, was the difference between a controllable 30ft deviation, and the side of the runway at the lower speed.
In aviation we often learn by knowing what the unknowns are; if we don’t know, then don’t do ‘it’.