Blade FlurryFollow

I just hit lvl 17 with my preditor last night and received Blade Flurry. All I can say is WOW! I was soloing at the time and noticed that every time it pops the mobs fall much quicker. Great spell but I have a couple questions about it.

I noticed that after casting it during combat, the icon stayed in the active tray and shows a duration of about 11 hours. Can I assume this means that I am getting the benefits of the spell for the duration? (It seemed like it but I wasn't sure.) Also, can it be cast while not in combat, like at the beginning of a session?

as of right now, you should turn blade flurry off when grouping with a chanter/inquisitor/coercer because when it procs it can land a hit on any mob engaged in the encounter, not just the one you are targeting. this could potentially (and it has for me) de-mezz the mezzed mobs. (although technically this is like fighting without a chanter, mezzing generates a lot of hate, and when you de-mezz something they will almost always go after the mezzer. it is also very frustrating for your party =P)