Battle Stance.

I did my best to search in forums and google but couldn't get what i wanted. And i'm new to warrior class so please excuse me for any mistakes. Gotta question regarding Battle Stance, when i switch to battle stance i should get 10% extra arp but when i mouse-over on my HIT to check i don't see the 10% increase. Is it like a hidden mechanic where it automatically gets/ increases 10% arp but doesn't show up in my character stats? I even made a warrior in blackrock and saw that there wasn't any 10% arp increase going in Battle stance.
Ty

Yes it will not show, but it is stacked additively, so if you have 90% it will translate to 100%.

"The ArP "buffs" (items, stances and such) stack additively too, meaning that 90% ARP on battle stance for a warrior would mean a 100% ARP final." (wowwiki)

thank you for clarifying.