Pilot reported ground conflict with a hovering helicopter on an FBO ramp as both aircraft responded to the same marshaling signals. The pilot stopped and turned away from the helicopter to avoid further conflict.

Narrative

I landed at ZZZ at XA:40 on DATE. As I taxied onto the non-movement area of the FBO after landing; a Bell helicopter passed behind me as I turned into the FBO to park and left my field of view. I followed marshaller instructions to the parking area . At this point; the marshaller started waving his hands as the helicopter began to follow and overtake me from above and behind so I stopped the aircraft. The helicopter went into a low level hover. I then encountered severe rotor wash and took an immediate left turn on the ramp as evasive action from the helicopter who was overtaking me. I then followed marshal instructions to continue to park. The helicopter then landed on the opposite side of the ramp without further incident. The marshaller stated the helicopter appeared to not have me in sight and that the helicopter mistakenly assumed the marshaling instructions were for him instead of me. I called the ZZZ Tower to report the hazard and they stated that it is non reportable on their end since there was no collision and this was in fact a non-movement area that they are not responsible for and the best course of action would be to reach out to the pilot of the other aircraft to discuss.