It's all estimated bollocks when using a dumb trainer.
Ride the bike on your turbo again but tell TR that you have it on a higher resistance setting. A nice tempo effort should be around 180-200 watts. You don't even have to do it as a test, just do a free ride session. That's what I had to do to get a reasonable figure with my old dumb trainer, it read far too low, but not as low as yours!!!
@Sam
It's all estimated bollocks when using a dumb trainer.
Ride the bike on your turbo again but tell TR that you have it on a higher resistance setting. A nice tempo effort should be around 180-200 watts. You don't even have to do it as a test, just do a free ride session. That's what I had to do to get a reasonable figure with my old dumb trainer, it read far too low, but not as low as yours!!!