it really isn't a question as such
It seems to me that the poison is poorly designed. Having a poorly designed example seems to me to be bad. I don't know of any other feedback for Fred so it seemed to me to be the place to post it. I'm sorry if I put it in the wrong place. It is essentially feedback on the actual book Fred, not the rules themselves, although it is partly about the rules and how to use them.
I do understand that the -1/4 limitation applies to the dagger or other weapon that delivers the poison.
My point is that you could buy the poison as +4d6 killing with extra time and other limitations that added to the damage done by the dagger. Since the dagger has to already have done body for the poison to take effect, there is no need for the poison to be an NND. The poison ignores defenses because the damage done has already exceeded the defenses. This would be vastly cheaper.
I have seen poison darts done before as an NND where the defense against it is having resistant defense - making it a +1/2 NND.
To me it makes more sense for the curare to be a +1/2 NND, not a +1 NND with a -1/4 limitation.
As an added note, should "does body" be a +1 advantage even if the NND is only a +1/2 advantage? Or should it double the value of the NND?
So in conclusion I would do poison one of two ways: +1/2 NND defense is having resistant PD with the does body added, or as HKA which adds to the damage done by the weapon with the limitations of delayed onset, and maybe then a -1/4 limitation that it only takes effect if the dagger did damage.