Hi,
A couple of things.
First I'm assuming that the 6 Bg(O), 2 Sp(O) and 10 TF is a separate 4th command? If so you can't have the Sp in the command as this type of "Baggage" command can only have Train in it.
Now lets assume you have substituted two Art in the command instead of the spear (and the army list allows you to do that). The command is not lost due to the 2 ME penalty, because that penalty only applies if a command has already lost an element. I'm assuming the baggage is not being sacked.
Now lets assume that someone is sacking your baggage and you HAVE lost an element. Then the 2 ME penalty would apply. And YES, the command is broken (but only at the end of the bound). Each surviving command also sufferers the 3ME loss due to the loss of the baggage command. But not for the reasons you state. The 3ME is because the 6 baggage elements are giving 1/2 ME each to each contributing command. If an element of these commands is within 800p of the baggage command, and have also lost an element, they get an extra 1ME lost for that (1 ME because the baggage command was less than 10ME).
So yes, the cumulative penalties can be very important.
And, yes, the baggage is static and doesn't go anywhere.
Hope this helps,
G^is,
JohnG