This graph above is posted by TrickZZter under
Gaijin made a mistake while repairing 99A // Gaijin.net // Issues The value clearly does not align with in game values. Where he said:
Spoiler
There is no error. In the previous major update 99A had incorrect visual model and incorrect armor. Almost all issues have been fixed in 2.39. But in some places the volumetric armor had intersections, which is why it did not work correctly. As a temporary solution, the developers disabled volumetric armor immediately after the release of 2.39. On the 24.09.2024 Production got resource update with corrected armor model. Players mostly have not noticed this change because volumetric armor was still disabled. The developers took a pause to allow everyone to update their resources, and yesterday they enabled volumetric armor again. Which you can seen in the datamine. After enabling the volumetric armor all the remaining issues have been corrected. One of them was lowered protection at the lower corners of the upper armor plate.
Nothing has been fixed as of RN, any explanation from devs?