Under the CoP footwork, spirals and spins have a "level of difficulty" which determines the base mark for the element, before the GOE is taken. The ISU seems to want to make sure that the criteria for Level 1, Level 2 and Level 3 are spelled out as precisely as possible, for skaters and coaches as well as for judges.
Here is the official distinction for singles and pairs (start with page 3 of this PDF document):
For instance, the difference between level 2 and level 3 footwork goes like this:
Level 2: Mainly uses turns and steps of three different types (e.g., 3-turns, twizzles and brackets, and progressives, toe-steps and chasses).
Level 3: Must include more than three different turns (e.g., brackets, counters, rockers, twizzles, choctaws) and must include three different steps running in multiple directions.
Level 2: Three changes of direction.
Level 3: Four or more changes of direction.
Level 2: Change of speed during step sequence.
Level 3: Quick changes of speed during step sequence.
Level 2: Modest upper body movement during steps.
Level 3: Full use of upper body movement during steps.
Level 3: Quick changes from steps to turns.
Which skaters would you say have footwork sequences that qualify as level three? I would say Michelle excels at "full use of upper body," and "quick changes from steps to turns," but what about "four or more changes of direction" and "quick changes of speed?"