Rule 1: Don't use ellipses instead of proper punctuation.
Rule 6: The guide is focused on raiding at level 90, and as such reflects the latest changes on the beta, whether or not those have made it to the live servers. Also remember that sometimes tooltips aren't updated as quickly as the mechanics they describe. Game mechanics are handled on the Blizzard server and can be changed with hotfixes, while tooltips are stored on your computer and need to be changed with a patch.
Threat of Thassarian now increases Frost Strike by 40% down from 50%.
That's odd...the tooltip in-game still shows 50%...