Once again an FTP question

In my last breakthrough training I did a 20 minutes climb at 269 W, which was more or less all out. The fitness signature changed to 267 W, which is about 15 W higher than every other site predicts (Zwift, Garmin, Trainingpeaks all have my FTP between 250 and 254 W). Doing any trainings from the XATA with this fitness signature goes clearly beyond my capacity. Here’s the link to the mentioned breakthrough activity: https://www.xertonline.com/activities/53nwb5eqzvazmjse

At first I thought that my high FTP or Fitness Profile as a whole are because there are some powerreadings from running. So I reset my account and reuploaded the last months without running power. What happened was, that my FTP even increased.

My questions:
-) Why does Xert set my FTP at 99 % of my 20 minutes power, instead of 90 %?
-) How can I avoid this? And no I don’t want to flag breakthroughs, because they were breakthrouhgs and the 20 min W are correct.
-) How can I ever use an XATA training, when it asks too much?

BR Reini

Hmm, strange enough, now that I’m uploading older data, the FTP dropped to 254, while especially peak power increased dramatically and LTP dropped to a sensible value, too. Seems to get into the correct levels now.

I’ve had a similar issue. The Xert guys explained that my PP was low which affects TP so I did some 5 second PP intervals. After this my TP was more realistic.

Listening to the podcast on fitness signatures they explained that TP is different to FTP, in that Xert has TP at the wattage that your MPA starts to decline, not the wattage that you can sustain for 40-70mins like the more traditionally used FTP. It’s a slight difference but it does go someway to explaining why Xert sets TP different to FTP in other apps, that said, I agree that it can seem to set it too high for day to day training, after a recent 10m TT, my TP increased to the point where I would be doing exceptional race efforts every time I trained, which I can’t replicate on a day to day basis.