Elite Zumo Power Fluctuations


I purchased the Elite Zumo last week and after alot of trial and error have it working correctly in Zwift under BLE settings not ANT settings.

I have noticed however in ERG and normal mode that my wattage figures are never constant and fluctuate significantly on each pedal stroke : in average swings of +/- 20 to 40 watts.

Can anyone offer help how i resolve this, my cadence figures appear accurate and also remain constant. I also updated the trainer to the latest firmware after setting it up last week .