be careful to your power meter.
Inside, where the power meter in included in my home trainer, I have about 200W for my ftp.
For outside, myleft pedal has a power meter. And when i make a ramp test with my home trainer using both the power meter of my home trainer and of my pedal, I habe about 50W of difference. i.e. ftp 200W with the power meter of my home trainer, and ftp 150W with my left pedal power meter.