The subjective sense of "free will" is just what it feels like to take an action without having knowledge of one's internal machinery.

Having knowledge of this internal machinery won't take away "free will", and one isn't usually just surprised with decisions selected by an introspectively inaccessible process that then have to be enacted, there is an option of reflecting on the output of any given opaque decision procedure and choosing something else. The relevant uncertainty is about what you will decide, not about the procedure that will be used to make the decision. If you know what you'll decide, you have already decided; if you are still deciding, you don't yet know what you'll decide, and absent this knowledge, you are free to consider the possibilities.