Possible useful charts. Shown the confrontation between armor and AP shells.

I'm not saying that you are incorrect - but you don't appear to have factored in Armour tech improvements, at least some of which offset the AP techs.

Note that there may also be incremental improvements in armour quality that don't come from techs which would also make AP techs appear to do ...

After 1925, the improvement of AP technology no longer increased the depth of armor penetration.