It does not, the armoury tooltip is an error. You can confirm this by simply puttng on and taking off block rating gear in game and watching your block chance change exactly as you'd think it would.
The WoW Armory tooltip shows that it does, yet in-game there is no such mention.
Doing stuff in Excel now...any help is appreciated.
So wait. I haven't checked this closely but does the Dodge/Parry/Defense numbers actually represent the numbers pre-DR or post-DR? It says "Before Dimishing Returns" but the way you worded your response makes me think that it is actually displaying after dimishing returns.
the posted ones that you see (the totals) is post DR.
so if you see it say Dodge: 22.91% than that is Post DRs. the thing you are thinking of is when you highlight it says "Dodge rating xxx (9.5%) Before Diminishing Returns" that means the 9.5% is actually less than what is added to get you to 22.91%.
This is my understanding anyways. My reasoning is that there is a method you can call using macros that returns your exact dodge/parry and assume this is the method call used to display on your character sheet.