When playing a Dwarven Bard, I have the optional Favored Class Bonus
(Reduce arcane spell failure chance for casting bard spells when wearing medium armor by +1%. Once the total reaches 10%, the bard also receives Medium Armor Proficiency, if he does not already possess it.)
Does that mean that when the Dwarf gets the Medium Armor proficiency, it also acts with no spell failure? or just at the -10%?