Red Brown, just my 2 cents..
Any engine wth automatic governing system (piston or turbine) will show fluctuations due to governing itself-- that's normal. As you mentioned, you are in hover-- so, there would naturally be pedal inputs. These inputs adds more to the governing action, You may or may not have overtorqued the engine. From experience I have seen several overtorques to have the pilots complaining losing Tq indication afterwards. This is due to the Tach Gen shaft severance. Can't hide that from the tech guys! On the Bell, if I remember it right there is a torque tube on the overhead compartment. This tube's got serrations (slits) along its axis. Overtorques twist these slits.
Now, if your 40% fluctuation is happening while on cruise-- man, that aint fluctuation! That's surging either due to Bleed Valve sticking close or a faulty FCU. I've seen surges due to FCU contamination (on the AS350) and the machine fies (on the way down) like a Cobra swinging its head left and right.