As said above, I'm skeptical about making the Master of Both Militias a supreme commander above the whole of military militia. It's a relatively exceptional title, that merged MM peditum and MM equitum. I'm also surprised by the lack of mention of MM praesentales (but it might be because it doesn't appears in the ND)
That said, it's from the
Notitia Digntatum, so a certain given of de facto sitution is to be expected. But it's less because Stilicho was MM Utriusque Militiae that he was commander-in-chief than the reverse eventually. I'd even tend to think that his title of MM praesentales (chief of the troops close to the emperor) gave him as much leverage, or rather, the capacity of Stilicho to add-up titles and charges (which is one of the reasons of his downfall, actually).
So, I'd say it's less of a representation of the typical state of the Late Roman army, than a fairly acceptable description of the situation of the Late Roman army in the west in the early Vth (
pretty much like this theoritical order map) but it shouldn't be taken at face value given some issues (acknowledged missing parts, probably a compilation of two distinct, chonologically, situations, etc.)
This diagram is much more abstract (given its generalizing part), but should be used IMO coplementarily.
EVentually, neither of these diagrams should be taken as absolute sources but representation of sources, which ask for a deeper research.
