I know we have recently discussed this somewhere, but I can't find the topic.
Anyway, I have made some experiments if it is possible to turn true sight off if the player has a certain level of Obfuscate.
But it seems it's impossible to change things that are set in the npctemplate.
It might be possible to change the whole template, but I can't script something that does it all by itself.
Tuesday is Soylent Green day.