I agree it screws up the TSS and IF.
But if you are using Training Peaks, and your FTP setting is correct there, you will just get the raw power data ported over. TP will do it’s own calculations of tss and IF based on the stored ftp there. Your TR calendar would be screwed up though.
There is also another subset that could do this. Those who don’t care about the tss and stuff. If you are the kind of person who just loads up the next workout and doesn’t care about the all the fluff.
(The arithmetic is still wrong, but can be fixed. If you increase your FTP by 50%, then lower the intensity by 50% then they don’t cancel out! (e.g. if your FTP is 100 W and you are doing a workout at a flat 100% FTP, then you’ll bump your FTP setting up to 150 W, then decrease by 50% of that, so will end up training at 75 W.))
Just wanted to say YAY! Tacked on some Endurance minutes to the end of Fang Mountain today and to my surprise - after hitting 200% it went to…201%! 
- Was able to keep raising until hitting target endurance wattage. HOORAY and BIG THANKS! @Nate_Pearson
Agreed! I am really liking this new feature too.
Yup!quite a surprise for me as well yesterday during my WO… thanks @Nate_Pearson and the whole TR crew! Really appreciate it!
Any reason this isn’t available on windows desktop?
They are actively rewriting the entire desktop app, and this will be included in it.
They don’t want to put time into the old version.