Miscellaneous: Warrior Criticals inconsistent

[topgun1027]

I logged in and was killing on my Warrior level 57 and noticed when I critically hit mobs it would say :

Character Name lands a Crippling Blow!(421)

the next line which shows same hit just in regular melee text

You crush greater plaguebone for 440 points of damage. (crit hit dmg )
You crush greater plaguebone for 78 points of damage. (double attack swing)

another example (just looking at my in game melee text atm)

Character Name scores a critical hit! (120)
You crush greater plaguebone for 139 points of damage. (crit hit dmg)
You crush greater plaguebone for 75 points of damage. (double attack swing)

I do not recall the crit number being different from what the melee chat showed before. Is this right or is it calculating in blocks or double attack bonus ? Kinda odd to me. Why is it saying 1 number for the crit but its saying another also?