The Rend Skill

Hey,

I'm new to playing World of Warcraft and I'm struggling to calculate the mechanics for the Rend skill. I'm curious if anyone know how this skill is calculated, this is what I have so far;

(R2)

40 + 34 (Not sure how the 34 is calculated either but done for me in the tooltip) = 74

74 / 15secs = 4.93

Now that should mean that for every second this skill is active (total of 15 seconds according to the tooltip) the skill should deal 4.93 DMG but it doesn't it deals 14. Now to get 14 DMG I have to do;

4.93 * 3 = 14 (I did this because some websites seem to say that each tick is 3 seconds during the 15 seconds.

As you can see I'm getting really confused and struggling to work out a perfect build.

Please help shine some light on this matter.|||in addition to the base damage of the skill, rend also does bonus damage based on the weapon you're using, the slower the weapon speed, the more damage done. this is where the extra damage is coming from. then just to complicate things a bit more, rend does 35% more damage if the target is above 75% health.

http://www.wowwiki.com/Rend will give you the formula for rend's extra damage|||I wouldnt realy bother to calculate it, to be honest ^^ If you realy need to know something, there is always somebody who did the math, you just need to find it ^^ But taking all factors in account is gonna take you ages :)