I’m not sure what you simmed to get a result that much lower. Without seeing your simulation report, I can’t see how you set it up.
I imported your character directly from the log you linked and used the DW no miss script that I referenced. The simulation comes out at 931,500 DPS, close to the 949,000 from your log. The standard deviation is 57,000, so that is will within the standard deviation and nothing really stands out. Even without the extra potion of the old war.
I see you are in the 99th percentile for your item level, so having the simulation come out a bit lower is expected -
top ranks benefit from lucky streaks and lucky procs that get smoothed out in the simulator. Coming back to that standard deviation again - without changing your skill or even a single thing about your rotation, you can expect any given boss attempt to range between 865k and about 1 million damage.
Here’s a link to the sim that is based off your log: http://www.askmrrobot.com/wow/simulator/report/38fc90cc6e7047998c54f464c674c472