Weapon and armour differences between MBT and WW2

[Psiaczek]

narwan said:
There may well be discrepancies between the two versions that merit attention, BUT you should always keep in mind that they are different games. What works in WW2 may not work in MBT and vice versa. The balance of the two games is very different.

Narwan

I know these are two different games

But as far as I know they have a common period 1946-1949? Am I right? I can play battle between British and Soviet army in say 1947,in both games, using the same equipment? And in such case 17 pdr gun in WW2 OOB is stronger than 17 pdr gun in MBT.
But for example T-34/85 in WW2 and MBT are twins Same armour and armanent.

These are not radical changes but i would like to know reasons for them.