Skill understanding

The first part is right. The second: not so much. There's some footage of the skill in action. The Paladin does gain a boost in power. From what I can tell, you can sustain +30 weapon attack as long as you don't take touch damage. In 5 touch hits (which are guarded), you will sustain the +30 weapon attack for 30 seconds. It also seems it cannot trigger within 30 seconds of the previous cast.
Video Footage

You be the judge.

When it's activated, it completely negates the next 5 hits (GUARD is displayed) AND boosts WA until it runs out of time or hits.