A conclusion in logic is different from a conclusion in a research paper.
Wait. Have you been referring to deductive logic rather than deductive argumentation? That is probably the majority of the clashing. The conclusion in a research paper is usually just a wordy version of a inductive argumentation conclusion(since that is what it is).
I am worried that you are getting too tied up in "How it is supposed to be" since you have already said that the form was valid(if premises are true then the conclusion is true). This sounds very much like you were given a list of examples and anything that doesn't match an example must be the wrong way to do it.
Our current disagreements are
1) How informative a conclusion should be.
I said that the most informative conclusion is the most useful. (Argumentation)
You said the correct conclusion is the most simple. (Logic course)
2) Whether A, B thus A&B is a useful conclusion.
I said it is useful especially since I am using it.
You said that the conclusion needs to be "Some A is B". Which not only doesn't follow but would not be useful to the position at hand.
Perhaps we should table this for now while we address the topic in the PMs.