Penetration Chance is (AP / Armour)^2

And death/killing chance appears to be a straight (Damage/HP) chance.

Right then, some math.

As previously calculated, the conventional Challenger tank has a 36% chance of penetrating the answer of the TN variant, a 60% chance of killing the TN variant if it penetrates and as such a 21.6% chance of killing its target on any given shot. I presume that Steve rounded to get to his 22% chance. It also has an anti personnel weapon with 6 shots but we're ignoring it. While it would be a factor in battle, it would make a killing blow maybe once every 400 shots, so can be neglected.

The TN variant, in contrast, has a 277% chance of penetrating, so it can't fail. It also has a 166.6...% chance of destroying its target on a hit, so it can't fail there either. Its anti personnel weapon has a 4.8% chance of striking a killing blow, and 6 shots per round. It'd on average delete an extra enemy tank every 4 rounds or so.

As such and roughly speaking, for a conventional force to effectively defeat a TN level 1 attack with the same weapons classes and number of weapons it has to outnumber its opponent somewhere between two and three to 1.

Against TN level 4 this gets worse. Not because the TN heavy gun is better, at guaranteed hit and destruction levels rate of fire is more important and that's the same, but because of the crew served anti personnel weapon. While the one in the Leman Russ is a Heavy variant, TN level 4 the multiplier is 10, and we can start our calculations from there. It has a 69.4% chance of piercing the conventional tank's armour, and a 55.55...% chance of killing the target on break through. This means it has an approximately 39% chance of killing an enemy tank. Per shot. And it gets 6.

So, abusing statistics in ways it shouldn't, I posit that a TN level 4 Challenger tank can kill 3.4 conventional tech Challengers per round, while the Challenger has a 1.2% chance of killing even 1 TN4 equivalent vehicle. It would, on average, need to shoot 83.333... times to guarantee a kill. A conventional tech force would need to outnumber a TN level 4 attacker 7 or 8 to one to not be obliterated.

A smaller number than you might've anticipated, but still something that majorly favours the TN tech. The numbers will get more skewed until the TN tech force achieves an AP of 12 and a damage of 18 on its crew served anti personnel, as at that point the anti personnel gun is also a guaranteed hit and kill weapon, letting the TN force kill 7 enemy tanks with every round they fight. Further weapons advances will not impact the TN force's effective offensive capabilities, but armour advances will of course continue to matter.

A couple of questions:

Do those limits include the HQ itself?

Can we get integer multiples between each size? (Currently it's 1, 2, 2, 2, 2, *2.5*, 5, 4, 4 - Which just seems odd. Especially as a multiple of 2 feels inefficient.)

Historically, higher to lower command ratios have shifted between 2 and 5, with conscripts and militia more often approaching 5 lower commands to each higher command and more professional and elite formations more often 2 or 3 direct lower commands per higher command. This ignores things like company level attachments that serve as a regimental heavy artillery section, the signal unit or other small units of specialists. Those would skew things quite a bit if we counted them, because you can easily have half a dozen of those attached at the regimental or division level.