There's not necessarily a perfect number that works for every play. But in every example, he had room to be closer to the line.
I didn't say he did a good job by being at 8 yards. He was deeper and did a good job to step up into the pocket to buy time.
As others have said, it partly depends on the play that is called.
In general, I would think if he starts in the shotgun position, he is coached to take certain steps for movement to get ready to throw the ball. I never have paid attention to how many steps that is back.
The pictures could also be influenced by:
a) Did the O lineman do a better job of blocking the pass rusher farther back?
b) Did the pass rusher do a poor job of taking a good line to the QB?
c) Just before the picture, did TA move one way or the other that makes it harder for the O lineman?
d) etc....
Without knowing the exact plays that were called and what he is supposed to exactly do and be doing at the time of the picture, it's hard to judge if he did it correctly or not.
But, I'm confused by your conclusion that one is an example of him taking to deep of a drop and one is an example of doing it right when they both have the same depth from the LOS.
I mean ... I've watched the plays several time and and explaining what I saw. I didn't just grab random screen shots. If you'd like to watch the plays and give your own analysis, feel free.
I've explained the answer to your last question already so I'm assuming you're not reading it.