I guess for me the teaching of the two levels or elements of nibhanna is taught in this way because at the time of the Buddha there were lots of arahants walking around and clearly they had the six sense media functioning and it was perhaps almost as evident that they could feel pleasant and unpleasant feelings so people wondered about the body being sensitive to these feelings and how these are defined as being dukkha. It was probably difficult for people to understand the arguements I gave in my previous post then just as it is difficult for people to understand them now. If people back then were stuck with the idea that "the arahant's body fells unpleasant feelings and this is dukkha" and were not able to understand the idea that for the arahant there is no "I" that is related to a "body" and certainly there is no "having" relationship there....then perhaps the Buddha decided that teaching in this way can help build the conceptual framework to help people to penetrate the idea of no doctrine of self.....in other words the feelings which still arise in the body seem to be an issue for those who have not entered the stream but not really an issue for the arahant....an arahant does not suffer from these feelings as evidenced by, " the well-instructed disciple of the noble ones, when touched with a feeling of pain, does not sorrow, grieve, or lament, does not beat his breast or become distraught." The body has unpleasant feelings arising in it (nibhanna with residue) but the arahant is beyond acting from the basis of a "self" "having" this "body" with its associated "pain".
Having said all this I do want you to know that I have no problem with the view that an arahant is not completely rid of dukkha until parinibhanna especially when it is described as the Buddha has done in that the ending of dukkha in whatever way one wants to conceive of it is evident from the description....the arahant is "feeling no pain" so to speak even though the body does I guess. For me the "residual" for the first kind of nibhanna is not a real issue for me. As I have said, my view is that very likely there will be no end in the refinement of reduction of stress in my experience and the text we are discussing is perhaps evidence of this....if I experience 100% loss of stress but with residue then hooray for that...and if that's not enough there's always the without residue possibilitly too I guess........for me it's all good.
If you stuck an arahant with a knife would he/she jerk and squirm and cry out in anguish?...I don't know.