If I infer that pnrjulius means that it's influence if I cause someone to behave in their own best interest, and manipulation if I cause them to behave in ways not in their best interest, and we assume (as you say) it's best interest as judged by them, then presumably if someone intervenes so as to change my judgment of my best interests, that's influence if the judgment-change is in my best interests as I judged them at the time of the intervention, and manipulation otherwise.

I'm not really sure why any of this matters, though.