I don't get it, Pete.
It followed your facecut precisely.
That is what a whizzy is for. To counter lean.
If you wanted it to go more to the left, why didn't you aim your face cut more to the left?
If you wanted it to start out going straight, to get it past the roof, and then to curve left,You are entering the grey area, that I don't work in around buildings ( at least not that close to buildings, I don't).
To get the tree to do that, you'd have had to make your face and backcut level on the right side of the tree and put something in the face cut to break the hinge on the right side, once the tree was past the roof.
But like I said, that is entering the twilight zone of treefalling.