Yep you got it in one thrust limited, the problem with your approach is that when do you say that's high enough?? so FMC MAX ALT 384 you happy with 390 to CRZ after all what the FMC says is just a computers best "guess" based on all of the parameter YOU have entered plus the inputs from the AD.
It just don't get your point here, my margin is not a random personal all I was saying is that if forecast shear and large/rapid temp changes then i feel a little caution is safer than pushing all the way up for often no benefit other than WoW look at me I'm at FL410 and if your sat there at 100% to stay out of the yellow box you'll be burning more of YOUR companies fuel than i will be a few 1000ft below.
Lets leave it at that and agree to disagree.
