I can fire up another example today no problem.
This was from Monday using my Wahoo Kickr (soon to be gifted to my son 
), they yellow power line is smoooooooooth as glass in ERG mode on that unlike the helter skelter line from my Wattbike, also in ERG mode.
That kickr has ERG mode power smoothing on giving unrealisticly smooth lines
I hate ERG mode power smoothing - itās the devil
Go into the wahoo app and turn off ERG smoothing and then compare the two.
This is my kickr v5 with smoothing turned off for example - maybe better than your wattbike but not super smoothā¦
To be honest, it very well could be that I have been using ERG Mode smoothing for 5 years and donāt know how to ride my bike on a trainer 
if it FEELS different now thats an issue - but visually the graph looks ok.
I did a Rouvy 
workout this morningā¦and it felt proper as far as resistance goes. Iāll do a TR workout today at lunch and compare how things went.
Thank you much for the insight 
This. People need to try this experiment:
Stick your trainer in Resistance mode and pedal as smoothly as you can at 200 watts (or whatever) for 5 minutes. Look at that power trace. See the variation.
Now. Is it possible for you to produce a smoother trace? Possibly. Have another go. Any better? Try again. And again. And again.
After half a dozen rounds youāll reach peak smoothness.
It is physically impossible for you to produce a smoother power trace, and if you can do so in Erg mode itās a lie, because your legs control the trainer, not the other way round.
/rant
The Wattbike is doing what IT is supposed to be doingā¦the rider, has much to learn!!!
Tunnabora -5
THAT is flippinā gold! Well done.
Iām not going to say that Iām extra smooth ( Iāll leave that to John Smith) but I would say the tip that worked for me was trying to keep my cadence very steady. So pick a cadence and stick as closely as you can to that, and I reckon your power should settle down and become smooth.
So as you move through a workout and the blue bars change the resistance, thereās a few seconds as it adapts and then smooths out again.
Maybe that explains why the really short intervals are so difficult to execute. But that said, a really short interval outdoors is pretty difficult too.
Betterā¦slowly figuring things out 
Certainly, still have room for improvement.
Thank you everything for the insight and suggestions.
Cadence cadence cadence 
I think that I could probably keep my cadence at 91 with my eyes shut. But that has taken a lot of practice.
By the way, have you got cleats? That might help with keeping my cadence constant
I tried reeeeeeeally hard to keep it at 92 
Yes, SPD-SL. Itās a long winter here in Wisconsin, Iāll get a lot of practice
