THE PLT & FLT EXAMINER WERE ON AN EVALUATION FLT AFTER THE PLT'S FLT INSTRUCTOR HAD RECOMMENDED HIM FOR A CFI CHECK FLT. TO DEMONSTRATE A HOVERING AUTOROTATION, THE PLT HAD SELECTED AN AREA OF SOFT TURF THAT SLOPTED DOWNHILL. THE EXAMINER STATED THAT AFTER THE PLT CLOSED THE THROTTLE, THE HELICOPTER DESCENDED NORMALLY; HOWEVER, THE PLT APPLIED EXCESSIVE COLLECTIVE PITCH. THE EXAMINER REPORTED THAT AT THE MOMENT OF TOUCHDOWN, THE HELICOPTER RESPONDED TO COLLECTIVE INPUT, CAME OFF THE GROUND IN A NOSE LOW ATTITUDE, THEN TOUCHED DOWN ON THE TOES OF THE SKIDS ROLLED & OVER. REPORTEDLY, THE EXAMINER GRABBED FOR THE CYCLIC IN AN INSTINCTIVE EFFORT TO REGAIN CONTROL OF THE HELICOPTER, BUT MISSED THE HANDLE DUE TO THE UNIQUE CONTROL CONFIGURATION OF ACFT. THE PLT'S HELICOPTER TRAINING HAD BEEN IN 2 ROBINSON R22'S, THE NEWER OF WHICH WAS EQUIPPED WITH THE HEAVIER HP ROTOR BLADES. THE HP BLADES HAD A DIFFERENT AFFECT ON THE HELICOPTER'S RESPONSE & FLT CHARACTERISTICS DURING AUTOROTATIONS.