The argument has been made that this is sort of a misappropriation of the terms, because the levels are meant to define levels of understanding rather than levels of detail. I'm assuming what you're aiming for is that you can say to your student(s) "I'm looking for a level 2 explanation here", and they would provide you with an answer that would prove that they have achieved a level 2 understanding of that concept.
Thus, your table is going to look slightly different because it describes the type of answer you must give in order to prove a level of comprehension, rather than describing the level of comprehension itself. Note I may have misunderstood the levels above to some extent as I am familiar with the concept of levels of comprehension but haven't seen it formally listed in this form before (irony!). I think, even if you disagree slightly with my interpretation, the overall exercise will still be useful (I hope!):
Level 1 - It looks like it's true (The Duck Test)
"If it looks like a duck, and quacks like a duck, it's probably a duck."
It's a good phrase because it's memorable and it well-defines the concept. It also reinforces the lack of concrete data associated with this level of comprehension: "I can't prove it's true, but my understanding is that it's unlikely to not be true". This proves level 1 comprehension because... well, they have made a correct basic assumption based on the appearance of the problem.
Level 2 - I can deduce that it's true
"I have gathered some data on the objects in question, and can deduce that this is the case"
Note: Deduce, not prove.
To show Level 2 comprehension, the student must be able to provide detail to support their Duck Test. In the original example given, it would be to say "I have calculated the angles, I know they're both acute so my duck test holds". They don't have to then prove that the corollary (angles are congruent) holds to show this level of comprehension. This proves level 2 because they have used actual data to make a correct assumption (well, technically an assumption).
Level 3 - I understand the Importance of these properties
"Not only can I deduce that this is true, I can extend my deduction to related abstract concepts"
To show Level 3 comprehension (IMO, there may be disagreement here), the student must show that they understand the relevance of what they are seeing. What are the consequences of the these two angles being congruent? Can the student make the jump of comprehension to the other properties that must therefore be true (related pairs of supplementary angles, the types of geometrical shapes that would be formed from sets of congruent angles, which lines must be parallel if these two angles are congruent). Rather than just seeing it's true, how can I USE the fact that it's true?
Again, note that the student isn't required to prove any of this yet, just understand the significance of the data. I might be able to deduce from the sound on the roof that it's raining pretty hard, but will it occur to me to take an umbrella when I go outside?
This proves level 3 because they can volunteer consequences of the properties they are seeing, showing an understanding of the abstraction - they understand what it means, not just what it says.
Level 4 - I can Prove that it's true
"I know that this is true, and I can prove it"
The student shows comprehension of both the consequences of the properties and the base principles behind the properties. They can use these base principles to prove their duck test rather than just deducing from "stuff I know is true". F.Ex., I can prove that these angles are congruent using my knowledge of angles and parallel lines, rather than simply deducing it's true because I've been told that two parallel lines bisected by another line at an angle forms a set of congruent angles.
This shows level 4 comprehension because they can prove their deductions rather than relying on "facts" that they have been told (Ability to prove the theorem from axioms, definitions, and previously proven theorems, as opposed to merely knowing how to use the theorem).
Level 5 - I don't know that this is true (yet), but I can prove it
"I know that this is true (and I can prove it), but can I prove whether this is true?"
Student shows absolute comprehension of the subject, to the point that they can apply what they have been taught to prove things that they haven't been taught. Using their knowledge, they can make good assumptions about other things that might be true, and go on to prove and disprove them.
This shows level 5 comprehension because the student understands enough about the system to try and extend their knowledge beyond its current level.
"I know that this holds in this case, but can I be sure that it always holds?"
"This configuration looks interesting, can I use my knowledge of geometry to prove anything about it?".
It may not be exactly what you're looking for, but it's what I've understood your question to be asking for, and I hope it helps regardless! The unfortunate truth is that (in my experience) most students won't ever reach level 5, particularly in a compulsory subject, because it requires a significant level of enthusiasm to reach it. Maybe by showing the decent but relatively uninterested students that there is something to aim for beyond level 4 (which is sufficient to get you through pretty much any exam), it will encourage more of them to take that leap. If that's the case, then this will all have been worthwhile!