Have you done a separate FTP test on Zwift? I found that the Zwift test estimated mine slightly lower than TrainerRoad ( despite accurately measuring my tyre circumference ).
Without, although it would make no difference, as all you're doing is following a workout based on whatever Zwift/TrainerRoad 'thinks' is the correct number ( despite not being as accurate as a PM ).
Have you done a separate FTP test on Zwift? I found that the Zwift test estimated mine slightly lower than TrainerRoad ( despite accurately measuring my tyre circumference ).