I was thinking that Support Formations are maybe supposed to focus on one aspect of a battle, and not (say) get involved in close range combat (or summat like that...)?
In my games too many times all Brit inf units are used as interchangeable inf units, and it's unclear why one unit is a "support unit' when it seems to have basically the same weapons as a regular inf unit. And then IIRC there are "Maneuver Support" units. How are they used differently is what I am curious about.