I'm not sure I understand why that would affect anything.
I haven't heard of Despoil working on NM's and I haven't been able to despoil anything away from one myself yet either. If NM's are immune to despoil then it wouldn't be possible to use it on dynamis mobs because they're all considered "NM" status. However if Despoil does work on NM's then it may be possible to take stuff like M silver and whatnot. But that would be way too powerful (just think of despoiling relic armor away from standard mobs in dynamis) and you can see why "impossible to gauge" status matters. I think NM's have Despoil immunity; or at least the item part which is all that really matters to me since the debuff is random and too short lived to exploit.
Edited, Jul 5th 2010 4:05am by Melphina