Jolt Country

In the inventory screen, armor is shown with an armor class AC value. I was curious how the number shown here is calculated. For example, in the Ultima game the plate gauntlets absorb 6 points of damage 5% of the time according to the object settings, but the AC is shown in the inventory as 0.

The plate armor, by contrast, absorbs 7 points at a 75% rate, and has an AC value displayed as 5.

I think I may have answered my own question here... is it

AC = (points of damage absorbed) * (percentile), rounded down?

Yes -- that's exactly how, and only for the inventory screen (to give a sort of at-a-glance idea of how different armor compares in overall effectiveness) All the actual combat math uses the numbers from the object editor.