But what do you think about Barritus's option? Can you have Cmd Bge and Army Bge SIMULTANOEUSLY assigned in the same sub's command? Would it modify the ME counts?
Huh? That's not what I said! Read it again:
If you buy baggage for an ally general, the baggage must be assigned to that command. For other generals, baggage can either be assigned to the command, assigned to another sub's or C-in-C's command, or placed in a separate baggage command.
Nothing about simultaneously assigning Army and Command baggage in a single command.

It's all described in the section on Baggage on page 9 of the rules.
Here's an example: My Late Imperial Roman army has a Regular C-in-C and two Regular Subs. I've bought the maximum possible baggage, and placed it in a fourth (baggage) command. This means it's Army baggage. I do this because the fourth command gets a PIP dice of its own, making it a useful PIP dump.
Alternatively, I could leave each pair of baggage elements with each command, as Command baggage. That would mean I'd get only the three PIP dice, and no PIP dump.
If I wanted to, I could have one command keep its baggage as Command baggage, and group the other two commands' baggage together as Army baggage, which would still be enough to create a baggage command and give me an extra PIP dice.
Perhaps if you told us what army you've been using, and we could describe some examples for it.