"As you understand it" being the determinant phrase. The mainstream, normative, Islamic position on the issue isn't much different than what you articulated above in response to my initial question. However, there are indications that if we got down to a more explicit pronouncement on the matter, we would part ways dramatically. For instance, the notion that God changed His mind about a decision and repented from His actions is patently absurd in our opinion.
To the point: Putting aside theological conclusions about the veracity of each text as a Divine revelation, the fundamental difference between the Bible and the Qur'an as pieces of literature that you are ignoring is that while the Bible is principally a historical text of the biographical persuasion, the Qur'an is a unique work of prose that does not fit any particular category? Why? Because by-and-large, the Qur'an is a conversation between God and His prophet Muhammad (Allah bless him and give him peace), much of which was communicated in "response" to certain situations which were occurring when the revelation was being given. In that dynamic, to assert that having knowledge of the circumstances surrounding the revelation implies determinism is fatally flawed reasoning.
Likewise, your assertion that if something is prophesied, then determination is a non-issue, but that information being presented outright without that medium of prophethood is theologically problematic is the very sort of criticism that I am referring to. We also declare the sovereignty of God and the unimpaired responsibility of man. However, we additionally affirm the absoluteness and timelessness of God's knowledge, such that "changing His mind" and "repenting" are logically absurd. Consequently, His revelations regarding certain events prior to or concurrent with their occurrence in the earthly realm does not necessitate deterministic pre-destination. God does not become informed of events when they happen in time, so whether or not they were prophesied through a third-party or directly stated/implied/understood as they are in the Qur'an is besides the point when you affirm the timeless and absolute knowledge of the Divine.
But to appreciate this, you have to accept the Qur'an as the mode of literature that it is - and from my exposure to Christians, particularly those of the evangelical persuasion - that is not something you all are wont to do.