Answer

These two possibilities do not contradict each other. One question is what the rabbi ought to present, assuming he himself has his own position—should he also present other positions? The second question is: when he has one position, do you have to follow it?
The answer to the first question depends on one's outlook. Some would say that the rabbi should present all the positions. Rabbi Shlomo Zalman Auerbach writes this regarding rabbinic laws, and brings there that Ketav Sofer wrote it also regarding Torah-level laws. I do not think the rabbi is obligated to do this. If he has his own position, he should present it.
As for the second question, if the rabbi has a clear position and presents it to you, then if you came to ask him, you need to accept it—unless you told him in advance that you were only coming for consultation.
These matters are explained in detail in the third book of the trilogy.