L6/40 Tank: Armor oddities

I recently purchased the L6/40 (31 Rgt.) for fun and after inspecting the armor layout I noticed some oddities:

Firstly: The Vehicle is protected by 30mm of armor on the lower glacis and hull, while the gun mantlet is a mere 25mm with the mostly non-existing turret front being 40mm.
That seems kinda odd why the front of the turret would have less armor than front of the hull.

Secondly: The upper glacis plate above the transmission is 20mm thick. The plate is at an angle of 74° and not even the side armor of the vehicle is 20mm thick. This makes this part of the tank the most protected, giving it an insane amount of 74mm LoS armor.
However the transmission maintanance hatch is only 15mm???

That doesn’t seem correct. I read on the German Wiki and on Tank Encyclopedia that the gun mantlet is suppose to be 40mm thick. Of course there’s no source for it.


In WoT the armor is how you’d expect it:
40mm for the gun mantlet and 15mm for the upper glacis.


Now does anyone have any clue where to find some more accurate information on that?

All I got is this:

Which mentions 40mm of armor for frontal plates but is otherwise not very helpful.