I'm not going out on a limb on this as the 76.2mm fired a blunt nosed shell which supposedly did poorly vs vertical armor but better vs sloped armor.As an example of 'bad-logic', one can read the T34 test above, and apply it to something like a Panzer IV frontal armor which was often protected by tracks. The Panzer IV gets 200 meters of range protection from a 76.2mm AP threat. Why? because the T34 got that range protection. In reality, unless the hit was oblique across the frontal aspect of the panzer IV, the tracks would offer very little protection.
This is another case of the 'Did the Soviets nerf foreign gun ballistics numbers?' While it says the MV was 770m/s what did they set the charge at to simulate 1000m range? In the Yugoslav tests a Pak 40 (MV=790?) penetrated the T-34/85 hull to 1300m. While that was a 50% criteria of penetration the Germans tested a 75mm/L43 (MV=740) which penetrated at T-34/76 hull up to 800m.