Yes, that are light tanks for 70 fuel, that is a lot for a light tank. Take Puma for example, costs 70 fuel can damage a Centaur too. On the other side Ostwind can damage Stuart / T-70 pretty well by itself since it has a lot more penetration than Centaur. I don't mind that light tanks for 70 fuel have a chance to damage Ostwind/Centaur for 100 fuel.
Only there a major difference T-70/Stuart are light tanks Puma/AEC are recon/AT vehicles.
(Want to check how Luch does vs centaur?)
Calculate the change of the Puma hitting and penetrating a Centaur and do the same for AEC (or even T-70/Stuart) vs Ostwind.
No matter how you want to look at it Centaur is much tougher than Ostwind.
The target size is the real deal and I never questioned that. I said that the higher armor has little effect since there is only one typical matchup were it helps at all. It is the matchup PZIV shooting at a Centaur. All AT weaponary I talked about penetrates Centaur to 100% at long ranges. So the armor is worth nothing here. Overall the armor adds little survivability, more speed would be better. But of course the target size helps in any combat situation.
Armor does help Centaur it that simple vs a number of weapons.