Armor Check Penalty conflicting rules


This may have been covered in another thread but I couldnt find it...

In both the Atlantean and 2nd Edition core rulebook, for each and every class under "Weapon & Armor Proficiencies" it clearly states:
Note that armour check penalties for wearing medium or heavy armour apply to the Balance, Climb, Escape Artist, Hide, Jump, Move Silently, Sleightof-Hand and Tumble skills.
No mention of light armor causing a check penalty, correct?
However in the "Armor Check Penalty" part of the Equipment chapter it says:
Any armour heavier than a quilted jerkin penalises a character’s ability to use some skills. An armour check penalty number is the penalty that applies to Balance, Climb, Escape Artist, Hide, Jump, Move Silently, Sleight of Hand and Tumble tests when a character is wearing a certain kind of armour.
I assume that obviously I would deduct the armor check penalty for a Mail Shirt or a Leather Jerkin, correct? What is with this conflicint info in BOTH editions?
I have deferred to the D&D rules in this case... does anybody NOT apply the AC penalty for the ubiquitous mail shirt and steel cap?
I guess it is an editing problem, they simply copy-pasted the armor restrictions for the classes, but then added the specific rule about quilter armor. It is not the only error of this kind that you will find in the books.


Well, of _course_ ACP has to be applied also for Leather Jerkin and Mail Shirt. Why else would these types have an ACP value if you weren't supposed to apply it?

It's just a bit odd how such an editing error ("medium and heavy") could occur in the first place. It looks as though at one time it was planned to have no light armour with ACP in the game. Then they would have changed it back to incorporate the equivalents of Studded Leather and Mail Shirt, and forgot to re-edit that one passage about ACP.