Hey there, looking for some common mistakes I might be making in my gear or dps rotation that I am just not seeing. You'd think it would be pretty basic but my dps has been all over the place recently. 

I will be fighting kiljaeden (pretty standard) and have anywhere from 650-850dps average for the fight. It's gotten me kicked a couple times obviously despite being good on mechanics. I've reviewed several guides, made sure I am enchanted and gemmed... cannot figure it out. What am I doing wrong? (Yes low on meters for other fights as well though not always). 

924 iLevel, wearing legendary belt and chest (dont have tier to wear shoulders and chest)

67% Mastery (issue?) 
24% Critical Strike
29% Haste

Opener: Blood Fury, Tome (trinket), Crow, Bestial Wrath, Dire Frenzy, KC, AspectotW, Titan's Thunder, CS, KC, DF...

Repeat KC, CS, And cast DF whenever buff falls off or procs bonus. 

Talent Build is:
Cobra
Frenzy
Posthaste
Bestial
Int
Crow
Killer Cobra

Helps, tips, advice welcome. 

Are there common mistakes to rotation i might be making even if u dont see it here? Should i be working hard to gear swap? I am at a loss and it is getting frustrating. Thanks

I had my first ever RP experience that came out of no where with this random Gnome.
 
He invited me to join him on his 2 seater rocket....and then things got weird....
 
https://www.youtube.com/watch?v=tcmtQqbKSqY

So with the new iteration of SimCraft more accurately representing the 5.4 changes, I fired up trusty ol' SimCraft to see how Affliction and Destro would act comparatively in a Single Target, Two Target, and Three Target Situation. Interestingly enough, Destruction was the clear winner in all of them
 
However, the crux of what I am asking is that, I have been lead to believe that as the number of targets increases, the relatively value of mastery increases for destruction. However upon running sclae factors for myself, I found that that was not the case. I found that as the number of targets increased, the value of haste greatly increased. This continued with each target added (As I said, ran 3 sims of Both Aff and Destro) up to the point where a single point of haste was overtaking a single point of intellect. 
 
This just doesn't seem right to me, and seems to be against what I have been told to believe previously. I was wondering if there is some mistake in SimCraft or was there something changed that I am unaware of? I would never have guessed for this to be the case.. well.. ever.
 
Attached are SS, can also link the full HTML files if requested I suppose
 
http://imgur.com/a/Ko4TZ
 
 
Edit: I am aware that the one of the glyphs used is Everlasting Affliction, but I ran it again changing that for Healthstone Glyph, it did not change anything in any way shape or form