I'm in the process of putting together a dumb spreadsheet to calculate armor/stats etc. for all of my toons in one place. In the process I'm plodding through the various formulas to convert stats to the Armory page numbers.
Using the numbers there for level 60+ mobs I plugged in the boss level of 83 and then went to check against my armory page to make sure I did the math right.
The percentage was different. I plugged in the mob level of 80 and the numbers came out equivalent to what is on the Armory page.
Is the number on the armory page the actual percentage blocked on a raid boss (that is the attacker level is capped) or is it just calculating at 80 on the armory page, and the actual percentage blocked in damage absorbed is the lower number that I get when I plug in 83 as the attacker level.
it's for level 80s, as indicated in the tooltip when you hover over it. Boss reduction will be lower than what is shown, and the formula found at the page you linked is the accurate one to use against raid bosses.
I'm actually not seeing the information on the "as applies to level 80 mob" on the tooltip either in game or on the armory. (Just logged in to check the in game one.) Is there a tool tip somewhere other than on the character stats page that I should be looking at?