I think He does that in areas where He is going to act unilaterally.Paul referenced this i think in Rom 4 when he said "God speaks of things that are not yet as though they are" , so how does God do this?
I think when He prophesies something that involves human free agents it is obviously conditional.
It is not necessarily untruthful to make a prediction that doesn't come true. It may have been the right prediction given the circumstances at the time.It seems to me if God allows the possibility of being wrong he allows the possibility of being untruthful.
Let me turn the tables a bit...
Why would God EVER change his mind if the future is absolutely known already from his perspective? Why would there be any conditional prophecies, even, if God knew in advance whether or not the conditions would be met?