Hellknight signifier typos?

[Xavier319]

Alright, i love Hellknights, and have been waiting for the signifier for a while. I'm.. confused about it. It says it gains arcane armor expertise at level 2, which as far as i can tell, doesnt exist as a feat. Maybe they meant arcane armor mastery? also, at level five, it goes from a swift action, to an immediate action... doesnt your immediate action use up your swift action? and I fail to see the value of reducing your arcane spell failure during someone else's turn. So either these are typos, or the class is broken? If i'm missing something someone please point it out because I am slightly disappointed.

[Enaris]

I play as a signifer of the pyre, and I recently reworked my character. I'm assuming they meant Arcane Armor Mastery, and that is a typo; and the benefit of making it an immediate action becomes apparent when counterspelling, or when using the Ultimate Magic Spell-Duel rules. Also, my group is playing with the assumption this -also- allows you to cast immediate-action spells like feather fall with the reduced failure chance.

I'll point out we thought this was a silly rule, and we're playing that you don't need to take the swift action to reduce spell failure at all, until the rule is set properly.

I'd like to get an official ruling on all of these actions, in any case, but I hope this helped you.

P.S. When I say counterspelling, I mean as the counterspell subschool wizard, which allows you to counterspell immediately.

[Patrick Renie]

The miswording in the Hellknight signifer's Arcane Armor Expertise ability was an error that slipped through development; the first sentence of this ability should be changed to match the following: "At 2nd level, if a Hellknight signifer has the Arcane Armor Training feat, he gains Arcane Armor Mastery as a bonus feat."

As for the 5th-level benefit of making usage of the Arcane Armor Mastery feat an immediate action rather than a swift action, the strengths of this make themselves known during certain situations, such as, as Enaris pointed out, counterspelling or spell-duels.

[Lilith Bathory]

How dose the immediate action help?

Immediate action from the PRD:

Much like a swift action, an immediate action consumes a very small amount of time but represents a larger expenditure of effort and energy than a free action. However, unlike a swift action, an immediate action can be performed at any time—even if it's not your turn. Casting feather fall is an immediate action, since the spell can be cast at any time.

Using an immediate action on your turn is the same as using a swift action and counts as your swift action for that turn. You cannot use another immediate action or a swift action until after your next turn if you have used an immediate action when it is not currently your turn (effectively, using an immediate action before your turn is equivalent to using your swift action for the coming turn). You also cannot use an immediate action if you are flat-footed.