Weapon and armour differences between MBT and WW2

[Psiaczek]

Hi,I am comparing MBT v3.5 and WW2 v2.5 OOBs.
I see some weapons - for example british guns - 6Pdr, 17Pdr, 77mm Comet gun, american 90mmL52 tank gun. Their range and armour penetration are different in WW2 mobs and in MBT mobs. In MBT mobs I see weakening of these weapons.

The same about armour - for example Britsh tank Centurion Mk.2 in WW2 OOB and in MBT OOB - different front turret, front hull, side hull (in WW2 OOB 19FH 18FT,9SH in MBT 13FH 16 FT, 5 or 6 SH )

My question is :
1)Are the differencies because of not the same penetration algorithm in these two games?

2)Because of scalling -for example it is known for weapon A to be penetrate front hull of the tank X from the 1944,but it is also known weapon A is not able to penetrate front hull of the tank Y from 1960

3)Some other reasons?

By the way , could you give me viable links on theme: Centurion MBT armour protecting scheme in all versions . Some sources available to me claim three thickness of front hull :76mm, 118mm, 152mm sloped about 55 degrees.

But I can't find data about front turrets thickness in versions