Elite novu v stages PM left side

A bit of a complicated one for you all. I have been using my Novu elite smart trainer with built in PM the last few years and my recent ftp was 220. So I got a stages PM recently and I done an ftp test which gave me 220 as well. I do notice the stages reads a higher output of power for the same effort as on the Novu so therefore I thought my new ftp would have been higher but maybe just a bad test. After a week or so using stages I done a workout today and going on the power I was putting out my ftp should be bout 250 because I put out bout 30 watts extra for every interval. It was Williamson +4 I think. It seemed like a huge jump in fitness. I have had a good few months on TR so I am feeling strong but just curious as to why the sudden jump in power. I never calibrated my novu trainer before and I was using my garmin today and it was reading the power from my stages only and was matching up with my power on TR with stages. Anyone else have this experience?

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You can see the difference in my last two rides here.