Max: 100% and 110% for 15 seconds during autorotation. I'm assuming they mean practice autorotation, but how is that even going to happen as you roll the throttle off?
If the auto is started by dumping the lever before rolling the throttle, the sudden unload will result in N2 climbing, until the governor reduces the fuel in an attempt to get the RPM back in limits. The N1 might be almost at idle, but the rotor being driven by the airflow has completely unloaded the N2, so it might go high.
Often, also, you don't get a needle split, and the N2 will follow the rotor RPM up into the red range in turns and flares.
Check that you have a Bendix FCU, if you are running a Chandler Evans (CECO) it will always drag its feet when it comes to maintaining RPM.