Can't ride easy?

Did a ride tonight just doing a route rather a workout which I usually do.

Tacx Neo through Apple TV

In my easiest gear on the fairly flat Sprinter's Playground with Tron bike 90rpm was over 150 watts at 0 gradient. That seems off to me? I can do workouts pedalling 90rpm at 100 watts in erg mode on the big ring, can anyone think of a reason why non erg is so difficult? Trainer difficulty was at 50% at the start, I dropped it to 30% which didn't really help.

My FTP is currently only 200, was hoping to do Z2 today but even on an easy course it was mainly Z3