So what it looks like you demonstrated is that subordinate units don't benefit from superior commanders' training bonuses when they have no commander of their own.
You didn't show whether they benefit or not if they do have a commander.
Try giving one of the other subordinate commands a commander with zero ground training attribute? That might be interesting.
If you look carefully some formations do have commanders and some don't. I normally play with auto-assignments and never in my life have I seen a formation with a commander with 0 training get it's morale over 100 even if the parent formation's commander has a training score.
I did look carefully. As best I can tell, the one subordinate formation that has a commander also has morale above 100. None of the other subordinate formations at morale 100 have commanders. That's why I made the suggestion I did.
Of course, if you wanted to make a real test of the proposition, you need two separate superior formations, each with a subordinate formation. Give both subordinate formations commanders with the same training rating, and the superior formations different ratings...