Sun of sand,
Michael pretty much said what I would have in response to your posts.
Two thoughts that I might add though.
First, is that it is pretty obvious that Ansel tested his materials thoroughly, we have the books and such to prove it.
There is no doubt in my mind, that the instant Ansel figured out he had underexposed the Moonrise shoot, he understood exactly the challenges he would face and the options he had available. Peter did not have that same luxury so he asked for help.
Second, is the thought/fact that "perfect exposure placement" is a subjective thing that falls within a range defined by a specific photographer for a specific shot. There is no universal standard for best exposure.
This morning I have the great good luck to have a gorgeous Iris in the garden that has just unfolded. Got TMY and Portra 400 in the backs for my RB and playing with both from 400 down to 12 depending on the DOF. Both rolls will be developed normally. I have no doubt that every frame will be nicely printable clear out into the highlights