Slitherine

What happens when you reach research level 6 (the maximum) in a subcategory of tech? For example, you reach Tank Destroyer Tech Level 6. Are your research points then split between the two remaining techs (Blitzkrieg and Armour)? Or are they still split between all 3 techs? From experience, I think it is the latter. I think this makes sense, although I would propose that if you reach level 6 tech in a category where there is a focus point, the focus point automatically goes away.