A: Check the options (/clcdk) and look under "Disease Options" and make sure its set to what you want. Q: Does it work for tanking? A: Yes and no. While it shows you a basic single target rotation, it will not show you when to use cooldowns, or when to use more aoe threat ...
Back in wotlk, unholys hit like a truck and that is because they sat in blood presence (which was a dps presence) which increased dmg by 15% and 1% healing from dmg done (i dont exactly remember) but unholys would literately drop a target below 50% (from 100%) in 1 scourge strike...