Deadly Magic Blow, yay or nay?

should i get it? at level 80 i will have majority of the skills i want with a few on level 1 but what about this one. I am a stager since there really isnt any point going pvp build until 2nd rb, just going to make staging harder.

my pros
adds damage to all the skills
10% or 1/10 ontop of current deadly blow
increases damage by a lot if successful
only other way to improve maxed skills

my cons
not a skill
takes up 8 skill points
screen shakes slightly when crit, may get annoying like Tia

you can set it so that the screen won't shake when crit are hit, also, i would recommend you put 1 point on deadly blow, since lev 1 it's already 3%, and yuki have many long chain skill along with short cd, 3% is enough imo

http://lunian.genin.jp/calc/LSC/?name=Yuki&lv=80&rb=1-0-0-0-0&pt=99&val=B00BA0BB-000A00B-1111-0000-08804

This is the build im considering, i dont feel i need any more skills because i have enough time just to spam all of them and its a mix of ranged ,close range and freeze(stun) skills.

its not 10%
deadly magic crits are only 33%+ damage
physical crits are only 50%

therefore 10% x 33% = 3.3% bonus for max
-.-

they need to change the wording then

this is my build
its mainly stage, but is also set for pvp.