IMO, you can't generalize grey zone to red zone. There are too many unseen factors that be may at play.
Just in this example for instance, this pony's insulin could play a major role. I'd want to know that if he were here. And I'd be paying close attention to any foot/hoof wall changes, even if he is not overtly sore. Also short muscles in the back, eg., "topline Issues".
The point, I believe you have to look at each individual for grey zone/red zone lines.
Nancy C in NH
ECIR Moderator 2003
ECIR Group Inc. President/Treasurer 2020-2021
Targeted release of recordings of the 2021 NO Laminitis! Conference -- stand by!