100% - Plus or Minus Control

Hi I have a question that I cannot find any answers to anywhere in Zwift.

On the left of the zwift screen whilst training, there is a guide as to what part of the training session you have scheduled you have completed. If you have hit all the numbers you get a yellow star. BUT at the bottom, there is a 100% plus-minus control I have attached a screen shot with the section circled. Can anyone at Zwift tell me what this does and where the instructions relating to it are please?

Zwift%20Screen|690x371

That is there so if you don’t feel your best on a given day, you can decrease your ftp up to 5% for that workout.

As Fez said, it allows you to scale up or down the intensity but I believe it allows +/- 10% (not 5%).

@ Fez_Rockbottom and Kevin_Brown1 Thank you both for your replies, they will help me with my training. Could you tell me where did you find the information in Zwift?

I know it from using the feature from the companion app. A quick search turned up this news article from Ziwft:

https://zwift.com/news/4966-how-to-adjusting-the-difficulty-of-a-zwift-workout

Hi Kevin, thank you very much for the information I really appreciate it. I tried so many searches to find this information maybe I was just asking the question wrong.
Thanks again Geoff