i hate this thing... it was my only "good" drop. im a whm or blm semi-retired taru, i dont do the nin thing as taru, my mithra does it. they need to make rare ex items exchangeable with in the same account, i dont care u think not! NPC'd it for 3k
The latent is activated after using the weapon as your main, in 500 weapon skills. There is also rumor that the 6% is more often then that....I'll post some parser results someday.
Even if the 500 WS were reached, I doubt the picture of the weapon would change... the latent effect would just be in effect.
For example, when you do the trial weapons, their picture does not change upon completion, the latent just disappears (the opposite of these proposed weapons).
So really, how is anyone going to "prove" it... unless there is a really obvious difference in dmg output or critical hit rate.