Cluster Munitions - Capable to destroy tank?

[PlasmaKrab]

Now I start to wonder that how this is possible because I don't believe that cluster munition is more powerful munition than 155 HE?

Yes, it is, if you consider that anti-vehicle submunitions are shaped charges and therefore penetrate more armor than blunt PIBD HE shells.

Also they have more chances of hitting a tank because of the sheer number of submunitions per shell. I know that arty shells can be placed quite accurately in good conditions, but in game terms, you still have one shell in 2500m² (one hex), while the same one round can contain 50-60 bomblets (from the top of my head), that gives 50m² per bomblet.
Given the average top-view surface of a tank is roughly 3x7m so 20m², you have about 2 chances in 5 that a tank will take a top hit that will penetrate its roof armor. And as I wrote previously, a "kill" in game terms is a very loose definition, say a weapons and motor kill or the crew being knocked unconscious is a kill.
So with a good margin, you have one chance in 3 that a DPICM round will "kill" a tank if it hits the right hex. Now I have no idea how much surface a 155mm cluster round will cover, but I have heard that they are designed to endure a spread pattern of at least 1 bomblet per tank-equivalent surface.
Much headache for not much result, I know