This actually happened to my wife, but for the sake of simplicity I'll talk about it as if it happened to me.
I wrote a final exam for a university course last week, and a couple days ago I got my marks and the correct answers back. I disagreed with one of the questions I answered wrong, so I pulled out the textbook that was assigned to this course and found that it supports my answer. I sent an email to my prof with the page number and the exact quote from the textbook that supports my answer. His reply was (with slightly changed wording):
In class I said that correct exam answer... This is an issue with any text and shows why class is so vital: Texts rapidly go out of date or (such as the broad text used for this course) demonstrate a lack of depth. Lectures are usually much more up to date.
Keep in mind that this is an Archaeology class, which in my unprofessional opinion really doesn't "go out of date" all that quickly. The textbook is the assigned textbook for this course by the university. The online lecture notes posted by the prof make no mention of the disagreement. I was not present at the lecture.
Do professors have an obligation to recognize the assigned textbook as an authority in the context of the course? In my experience, when confronted with such a problem they typically go "Ok, fair enough, I'll give you the mark", but are they just being nice or are they supposed to do this? He's not a senior prof (not even PhD yet), so do you think going to his superior would help?
If I get this one extra mark it will bump me up 0.4 GPA for the course because I'm right at the cut-off.
Since several people asked, the question was something like "Which Aztec god is the god of war and is associated with water". The book said one god, Huitzilopochtli, was the god of war, while Tlaloc was the god of fertility and rain. When studying for the exam, Huitzilopochtli stuck in my head as the god of war, so I picked him. The prof said that in class he mentioned that Tlaloc also had militaristic aspects.
Note that I'm not saying the prof is wrong objectively, only that our book makes no mention of Tlaloc being war-like and instead makes emphasis on fertility and life, being a beneficial god, which seemed totally opposite to war. When I sent my email I explained that I picked Huitzilopochtli because the book lists only him as the war god, but that I recognize my answer is only half-right due to the water reference, and that I feel that Tlaloc is also only half-right since he's not a war god.
Also, the prof agreed with me that the book was misleading, but said that I should've come to the lecture. Hence my question here focusing on whether the book should have any authority without getting into the details of the question itself.