I would not equate a lag in the time between when the conscious mind is informed of a decision after the brain made it a lack of free will. I do find it unsettling that a scan could tell me what I am going to do before I consciously do but it was indeed my brain that made the decision which my conscious mind is part of.
It all boils down to whether or not you, having chosen something at one point in time, could've chosen something else instead at that point in time. If no, then that's determinism regardless of whether the decision made was constructed in the brain or not.
I've noticed many people have opted to redefine "free will" so that they could fit it with the idea of determinism, but that's just running away from the key issue, which is that traditional free will and determinism cannot logically be reconciled together. And free will itself is illogical anyway.