When you're worrying about your tanking DPS, please recall that fights have mechanics that take precedence over DPSing. You have Adds to pick up and fight, which can distort DPS meters if not configured correctly. Other times you're avoiding things, dodging things, doing other necessary mechanics.
Not many bosses are 100% uptime on mobs for you to continue parsing high DPS. looked like you didn't have Internal Release. That's a really good cross CD with super short CD, and lasts long enough to be worth it.
I usually get around ~300+ on T13, at ilvl124, and it involves a lot more running around and down time from whacking mobs.
So yeah, point is, keep it in perspective of the fight. Don't just focus on the DPS numbers....that's what DPS classes are for. :P