I'd love for the Level 4 discussion to be here in the thread. I want to learn as much as possible and think this is a fascinating topic.
Ask sincerely and ye shall receive more info about twists than you probably wanted to know.
Random tech panel info about twists: Twists can be downgraded if they are ½ rev or more short, but twists can’t be called underrotated. Why? Two reasons: The call of the rotation of a twist stops when the majority of the lady’s weight is supported by the man (or the ice

) on the catch/landing, not when the man’s hands touch the lady and at what moment does he support the “majority” of her weight (which would take forever to review), and twists are executed on the diagonal and did the man step 180 degrees exactly and how does that count towards rotation, and her right shoulder and her left shoulder are often pointing in different directions, and…
In pairs, the fundamental focus is always the safety of the skaters and a number of rules reflect that. A slightly overrotated twist is very dangerous (the man is likely to get an elbow to the face; triple twists are the primary cause of concussions among elite skaters, and the position of the two skaters makes it less likely that the man can effectively grab the lady). It is significantly safer to have the lady slightly short of rotation because it’s much easier for the man to get his hands around her.
The pair community has a shared interested in keeping skaters alive without life-changing injury.
There are five features for a twist.
1) Lady’s split: at least 45 degrees from the body axis with both legs straight or almost straight. This feature is usually assigned to the TC to watch. The split can be achieved at any time between the lady’s pick and the man releasing the lady.
It’s common that one leg splits far more than 45 degrees from the body axis and the natural inclination is to follow that leg. If you are training yourself to look for the split in real time, one of the keys is to retrain yourself to follow the other leg. The viewing angle can make a big difference here.
2) Catch: the lady must be caught with the man’s hands at the side of her waist (it’s common one of the man’s arms will be wrapped around her back or his hands will be in her armpits) without any part of her upper body touching the man.
The catch must stop the momentum of the lady’s descent: it's uncommon to see a top triple twists at the World level where the man has his hands on the lady's waist with no other contact and he doesn't decrease her momentum, but it’s common on singles and developmental doubles. The easiest place to see this is Intermediate teams doing singles: on some of them, the lady will be an arm’s length from the man and the only contact is his hands on her waist (his hands may or may not have left her waist: sometimes they turn a single over without ever letting go!), but she’s so far away from him that he can’t stop her momentum at all.
A full collapse is easy to see. The hardest thing to catch in real time from the position of the tech panel is the lady’s right arm hitting the man’s left shoulder (teams position their twist so this is blocked from the tech panel).
3) Lady’s arms: at least one full rev in the air, one or both arms over the lady’s head.
Pop quiz: can this feature be awarded on a single twist?
4) Difficult take-off, which is still referred to as “steps” because that was the feature for many years.
The movements must be executed by both partners. The key is that there must be a consistent rhythm to the movements with no loss or break in cadence. A dance lift, which is called a “small lift” in pairs, is allowed, but there must be steps immediately before the small lift with no loss of cadence.
5) Man’s arms: his arms must reach his shoulders while being “straight or nearly straight” as they descend. They do not need to be straight on the way back up and it’s common to see the man’s arms make a scooping motion: down straight, then bend the elbows and the hands come towards his chest on the way back up. To achieve the feature, there must be some kind of catch: it doesn’t need to be a clean enough catch to be awarded feature 2, but the man’s hands need to reduce the lady’s momentum before she hits the ice. Again, this isn’t common when looking at World-level triple twists, but it’s common with singles and developmental doubles and triples. (Developmental doubles occasionally look like a throw double Lutz.) It can also be an issue when a twist goes really wrong and there’s more of a “grab” to keep her from hitting the ice than a “catch.” If you see this, you’ll know: it’s not subtle.
Pop quiz answer: No, because the lady only turns a half revolution in the air on a single twist and the feature for lady's arms requires the arms to be overhead for a full revolution in the air.