I'm a bit confused by the last tip: "It's best to preemptively Cower rather than to pull aggro and then Cower. If you pull aggro and the Cower is resisted or isn't enough to drop you below the top aggro target then you're as good as dead thanks to the 10 second cooldown."
It's a 10s cooldown according to: http://www.thottbot.com/s27004
I'm changing the "global" to "10s" on the wowwiki page.
Changed rank 6 Edit
Ranks 5 and 6 showed identical threat reduction, which didn't make a lot of sense. I grabbed the number showing for rank 6 off wowhead, but I have no backup other than that for the number, if someone wants to double-check it. --Solitha (talk) 08:08, August 17, 2010 (UTC)