In referance to Ix'Aern Deed drops...if you fight them correctly, Deed drop is 100%.
Yes that involves holding both Qn's for DRK, both Qn's for MNK, all 3 Wyverns for DRG...but as long as this is done, my LS is literally 20/20 on all Ix'Aerns for Deeds. We've yet to get a Vice drop though, which leads me to believe that the manner in which you kill the mob, determines the vice or deed droprate. At this point we're only interested in Deeds and JoL...so we're not gonna jeapordize a 100% Deed droprate just yet.