I dont know why but my deeps wounds seems to be doing lower dmg than other arms war.
Here is wws from patchwork: Wow Web Stats
I am #14 on the list and I died early but still doesn't explain why #13 war deep wounds did more dmg even though my gear is better.
Range happens. You two have identical Rend ticks so it's not like the difference is gear. You guys both died at approximately the same time and he had less DW ticks than you meaning he rolled them higher. Which theoretically doesn't matter much in terms of damage done, but it implies that his DW's never fell off, and your's might have.
Looking at the buff lists you guys both had LotP and a ret Pally for 8% crit, you also had the 4 set T8 MS crit bonus and yet your MS crit rate was 29%... that's just unlucky, since toss in Cruely and Axe spec and your crit is already 28% for MS without looking at crit rating or agility!
He got lucky (he crit 73% on MS!), you got very unlucky. Your swings hit harder than his, he just crit more. You also ran as tight to slightly tigher rotation than him. So I'd just write this fight off as a fluke.