Hello! Sorry about the confusion here.
Essentially, the "broad" factor tells you if you've used the keyword in the document text at least once and the "appropriate" factor tells you how many times out of four that you've used the keyword (we recommend using it at least four times in the document text).
As you can tell, these are a bit redundant at the moment, but this is so that they can be broken out by importance. Using the keyword at least once in the document text is a critical factor. Using it four times isn't quite critical, but its still pretty important.
As far as the difference between "exact keyword usage in document" and "broad keyword usage in document", this refers to broad and exact in a way similar to how adwords thinks of a broad match and exact match for keywords.
So if your keyword was "tennis shoes", we'd say you satisfied the broad match requirement by using the word "shoes" and "tennis" in the document text within five words of each other. You would only satisfy the exact match requirement by using the words "tennis shoes" together in the document text.
I hope that answers your question. Thanks!
Miranda