To add to what Viper is saying, Anope only cares if the user is an oper, Anope has no clue what an "Net Admin" is. Anope only cares about it's own levels which are: User, IRCop, Services Oper, Services Admin and Services Root.
ircd oper levels are completely seperate from Anope access levels. There is only 1 setting OperServ cares about when dealing with IRCops and that is OSOpersOnly. OSOpersOnly, when set, is just that. Only IRCops can use OperServ. proper access is still required in Anope's list to acess it's commands.
[Edited on 6-1-2008 by katsklaw]