Let's presume that's we're using Infantry troops only, equipped with either Personal Weapons (Size 5) or Light Bombardment (Size 20)
PWs and LB have the same damage and AP traits, while Light Bombardment has 3 shots to PWs 1.
Let's presume that there's 2 parties to this conflict whose only relevant combatants are a total of 600 Size infantry Formations.
Let's also presume that one side has equipped its troops with Power Armour and the other has not.
Finally, let's presume that we can abstract away Fortification and the vagaries of random chance outside of non-integer results when dividing.
Let us first presume that both sides have 120 PW equipped infantry.
Both sides fire. Every unarmoured infantry unit dies. 1/4th of every armoured infantry unit dies. Definite advantage to the armoured unit.
Although both sides need to replace losses, the armoured infantry side has to pay
half the cost of the unarmoured side, and more importantly, still has units on the field with which to press the attack.
Let us now presume that both sides have 100 PW equipped infantry and 5 LB equipped infantry on the Support line.
Both sides fire, every unarmoured infantry unit dies, 28.75 armoured infantry units die, the attack is pressed likely killing another 3 or four armoured infantry units while wiping out the Light Bombardment infantry units. Unless a Breakthrough was calculated, in which case I'm not sure what happens but might be resolved in the same combat round.
Still a massive advantage to armoured infantry presuming similar numbers.
Let's check on the same cost idea.
This means that the unarmoured side has twice the numbers of the armoured side.
240 unarmoured infantry against 120 armoured infantry. Both sides fire, half the unarmoured side dies, and so does half the armoured side. This repeats until the armoured side hits 7.5 units and the result becomes a toss up to who gets the advantage.
Let's check with LB weapons.
200 unarmoured infantry and 10 LB weapons against 100 armoured infantry and 5 LB weapons.
Both sides fire, 230 shots go out against 100 armoured infantry and kill 57.5. 115 shots go out against the unarmoured infantry and kill 115.
85 unarmoured infantry are left with 10 LB weapons, against 42.5 with 5 LB weapons.
115 shots go out and kill 28.75 more armoured infantry. 57 or 58 shots go out and kill 57 or 58 unarmoured infantry.
27 or 28 unarmoured infantry are left, against 13, 14 or 15 armoured infantry.
57 or 58 shots go out and kill 14.25 or 14.5 armoured infantry, offering a good chance wiping them all. 28, 29 or 30 shots go out and wipe the unarmoured infantry. There's a small chance there's 1 surviving armoured infantry unit left.
The unarmoured Support line has now become the Front line. The armoured Support Line
may have become the Front Line.
Presume it has.
30 shots go out and hit the armoured line, killing all LB units. 15 shots go out of the armoured line and hit the unarmoured line, killing all LB units.
Presume the armoured Support Line has
not become the Front Line because there's a surviving armoured infantry man.
30 shots go out and hit the surviving armoured infantry man, tearing him to shreds. 15 shots go out and wipe the unarmoured LB units. Small but definite armoured advantage due to preservation of Light Bombardment assets.
Overall: Slight advantage to armoured units in same cost combat, strong advantage to armoured units in same numbers combat.
The way I see it... you will want to use quality formations and lots of support element with good firepower to back them up. As in real life you want the main firepower to come from supportive elements, the forward elements are there to take and hold ground.
In modern day combat forward elements are there to find the enemy and keep them found. Support units will then deliver most of the damage while the forward elements keep the information up to date. This has basically been true since the Napoleonic era, where artillery became the main damage dealer to enemy armies.