Thank you for enlightening me on how you use the fitness/form/fatigue numbers.
I don’t really understand the whole zFTP calculations, but remember we use Critical power method vs. zFTP so slight differences there. You can read up on how we use Critical power here..
Those Zwift races and challenges can sneak up on you, IMHO. Stick to Athletica’s plan and sprinkle a race or two on Zwift carefully and you’ll start to see great improvements 
MJ