I'm figuring out a way to make armor reduce damage because it's stupid that it it makes you harder to hit. Only problem is damage resistance is too imprecise with the increments of 5. Question is, is there a property that can do this more precisely?

You can add damage resistance multiple times. Since the amount goes from 1 to 5 and you can add as much as you like, you can have it add to pretty much any number.

There's also damage reduction that does it for percents rather than specific amounts, though IMO it's not quite as realistic.

I'm figuring out a way to make armor reduce damage because it's stupid that it it makes you harder to hit. Only problem is damage resistance is too imprecise with the increments of 5. Question is, is there a property that can do this more precisely?

You can add new lines to the iprp_resistcost.2da file to add new resist values. Set how much damage should be resisted in the amount column and set the name column to a dialog.tlk strref number of an entry that contains the text describing the effect when you look at the properties of the item in-game (like "Resist 15/-").

If you have KotorTool set up to look for 2DA's in the override folder as well it should load your new resist values in the item property editor where you can use them.

What does the cost column do?

What does the cost column do?

I don't think it does anything in KOTOR, it's likely a remnant from NWN where it was used for automatically calculating the price/value of items where that property was applied. Since KOTOR doesn't use auto-calculated item values it shouldn't matter what you put in that column.

What I'm having to do to make this work is manually edit the xml for all pieces in the game. The first six defense points are now only physical and temperature damage resistance. Ion and energy resistance add after that. Nothing else is affected. The only quirk is per round reduction rather than per hit.