ALL penetration values in the game are for 0ยบ.
Please keep in mind that values calculated theoretically using ideal formula and real life penetration ability of the gun are totally different stories. Our values for Soviet and German equipment are based on tests documentation. Various nations used different methods of gun penetration tests, for example, Soviet tests terms were narrower. Because of this, most values for Russian and German guns are from authentic gunnery tables and gunnery tests data of captured German equipment. Allied guns penetration data was corrected by Battlefront.
If you want, you can replace all values with theoretical data, but this will be the simulation of ideal tanks and guns and will be far from real WW2 engagements. If most wargames just take values from Jentz and such books for German, another books for Russian and Allied guns and throw them together into the damage calculation system, it doesn't mean this is the right thing to do. These values were measured using completely different methods (or much worse, calculated theoretically) and can not be used together 'as is'.