Here is another example of a simple error of omission that could have been caught if the student had read the essay aloud or given it to a friend to read. The word "of" should be between "calculation" and "the." That one small error makes the entire sentence awkward and confusing. If the instructor has to reread the sentence to try to understand its meaning, the flow of the essay is interrupted. If this happens often enough in the essay, it gives an overall bad impression on what otherwise might be a very good paper in terms of research.
It is true that we cannot be 100% sure of what Socrates said himself as Plato wrote The Apology. However, as this is an account of a well known event, we can be sure that it is accurate (many other of Socrates' friends were present and Plato is less likely to have written something different when there were other people who witnessed the speech). Anyway, the Socratic Problem usually only arises in the dialogues that Plato wrote, not accounts. Plato did use Socrates as a "character" for delivering his own philosophical treatises as well as some of Socrates'. Many historians believe "The Apology" to be Socrates own.