Mithral Armor: Check Penalty

[Trasilor]

Mithral Armor reduces the check penalty by 3

All Mithral armor is masterwork. Masterwork reduces the penalty by 1.

Per SRD

Weapons or armors fashioned from mithral are always masterwork items as well; the masterwork cost is included in the prices given below.

Note that the ACP reduction for masterwork is not included.

Does that mean Mithral armor reduces ACP by 4?

[Lord Vukodlak]

Mithral Armor reduces the check penalty by 3

All Mithral armor is masterwork. Masterwork reduces the penalty by 1.

Per SRD


Note that the ACP reduction for masterwork is not included.

Does that mean Mithral armor reduces ACP by 4?

No, it reduces it by 3. Because Mithral armor is always MW. And MW always reduces the check penalty by 1. There is no reason for the two numbers to be kept separate.
Also Mithral Chainmail and Mithral Fullplate are included as examples under "Specific Armor" and only have a armor check penalty reduction of 3.

[Trasilor]

No, it reduces it by 3. Because Mithral armor is always MW. And MW always reduces the check penalty by 1. There is no reason for the two numbers to be kept separate.
Also Mithral Chainmail and Mithral Fullplate are included as examples under "Specific Armor" and only have a armor check penalty reduction of 3.

Then why bother pointing out the price combines them?

I always played it that way - I was just curios from a RAW perspective.

Of course Mithral chainshirt has an inconsistent weight (entry lists it at 10 lbs while mithral states it should half as heavy (12.5) :smallamused: )

[Seppo87]

I don't remember any rules concerning reductions not stacking. There are rules for bonuses, but nothing is said about reductions.
I believe, by RAW, they stack.

[Killer Angel]

I don't remember any rules concerning reductions not stacking. There are rules for bonuses, but nothing is said about reductions.
I believe, by RAW, they stack.

Armors fashioned from mithral are always masterwork items and armor check penalties are lessened by 3.

Any bonus given by MW quality, is already counted in.

[The Grue]

I don't remember any rules concerning reductions not stacking. There are rules for bonuses, but nothing is said about reductions.
I believe, by RAW, they stack.

This. My argument would be that the neither the MW reduction nor the material reduction are given a type, they are therefore untyped. Untyped bonuses/penalties always stack with each other.

This is different from the +1 attack bonus to MW weapons, which is specifically given as an Enhancement bonus.

EDIT: Swordsaged, and by the correct answer too.

[Zanos]

A mithral full plate of speed (http://www.dandwiki.com/wiki/SRD:Mithral_Full_Plate_of_Speed) has an ACP of -3. Since fullplate is -6 without mithral, this would indicate that mithral reducing the armor check penalty by 3 is all that you get.

[Anxe]

Its masterwork so you can turn it into a magic item without any additional work.

[TuggyNE]

Then why bother pointing out the price combines them?

So no one will accidentally double-charge for MW mithral. For that matter, since the wording is "weapons and armor […] are always masterwork", the listing includes all relevant changes, not merely price.