Benefit of Armored Kilt

Question

The Armored Kilt can be added worn alone or added to a piece of armor.

I always worked under the assumption that if you added the kilt the AC bonus was increased by 1 and the weight of the armor went up by 1 tier.

After a few questions asked recently(I have linked them below) have came up about the kilt though I realized I have never actually found any rules supporting this assumption.

Is it stated anywhere that the armored kilt adds it's AC bonus to the armor being worn with it? Or is the reverse stated explicitly anywhere?

If the armor is not added to AC what is the benefit of having the heavier armor?

Related questions:

What effect does combining... and How does the armored kilt work

Answer 1

Yes, it does add AC, but...
Not to anyone wearing heavy armor already.

The Armored Kilt in the Adventurer's Armory only says this:

Armored Kilt: When you add an armored kilt to a suit of light armor, the set counts as medium armor. Likewise, a kilt and medium armor counts as heavy armor. Adding an armored kilt to heavy armor has no effect.

This suggests that the Armored Kilt is nearly useless, but this description is only to "update" the Armored Kilt from Pathfinder Chronicles Campaign Setting, suggesting that anything not mentioned is not changed.

The PCCS has a very different description:

Armored Kilt: [fluff] An armored kilt can be worn separately as light armor, or it can be added to other suits of light or medium armor. Adding an armored kilt increases a suit of armor’s armor bonus by +1, but it adds 15 pounds to the armor, lowers the maximum Dex bonus by 1, and increases the armor’s weight category (from light to medium and from medium to heavy). Adding an armored kilt to heavy armor does not provide an armor bonus increase.

The classes that would find the biggest advantage in this are full Arcane Spellcasters. The Armored Kilt is the only piece of armor in the game that does not come with an arcane spell failure chance. This means that wearing it does not have a chance of causing any spell with Somatic components to fail.

Since having no armor does not come with any DEX penalty, wearing no armor and an Armored Kilt actually allows you to use your full DEX bonus, regardless of what your DEX bonus is.

Do note that it cannot be enchanted or masterwork-ed separately from your regular armor.

Answer 2

Yeah, it adds. The original description of the kilt was in the Pathfinder Chronicles Campaign Setting, a 3.5e product. The update of it in the Adventurer's Armory omitted the majority of the description. The original description says in the text (PFCS p.211):

Adding an armored kilt increases a suit of armor’s armor bonus by +1, but it adds 15 pounds to the armor, lowers the maximum Dex bonus by 1, and increases the armor’s weight category (from light to medium and from medium to heavy). Adding an armored kilt to heavy armor does not provide an armor bonus increase.

You can NOT enchant it separately, masterwork it separately, or material it separately.

Quoth SKR:

Adding an armored kilt to an existing set of armor has the effect of creating a new type of armor, just as studded leather is leather with studs, chainmail is a chain shirt plus leg and arm coverings, and half-plate is chainmail plus plates. Once you add it to armor, don't think of it as a separate piece that you can add unique properties to, just consider the new armor as a whole. Just as you wouldn't say "I want to add magic to the studs of my studded leather armor" or "I want the plate parts of my half-plate to be adamantine" or even "I want to add enhancement bonuses just to the padding of my full plate," don't try to single out the armored kilt as a separate piece.