First the reference info. If you go to the GHQ website, and look under the "FREE STUFF" section, you can find
MODERN MICRO ARMOUR®
Producing Weapons Statistics for Micro Armour – The Game
as well as:
Country Histories / TO & Es
Scenarios
Caveats: GHQ is currently in mid-transition to a new website. So links and content may be a bit unpredictable.
Now to the questions. I am not in any way affiliated with the authors of the rules, so don't take this as somehow the "official" word. I am just a gamer.
I do not think you need to use the TO&Es. I have never come upon a miniatures ruleset that said you are somehow required to abide by their TO7Es. They are provided as a reference/convenience.
If you look at the GHQ scenarios, they often have forces that are not in the TO&E tables. This is true for GHQ, as for many other rulesets.
Sometimes there is a "convention rules" sub-set of the rules that define rules for competitive environments. In that case you might find rules that must be adhered to in constructing a force for "fairness of play". But most of the time (I would say 95% of my own games) the gaming is not under "convention rules".
For me, I never even consider the points values when I build a force or a scenario. And my own knowledge of TO&Es is frequently better than what's in the rules, so I will often disregard that, too.
Your tankage may vary.
-Mark
(aka: Mk 1)