The angle the bullet is pointing to is driven partially by the ratio of the wind speed and the bullet forward speed so as the bullet speed changes then that ratio and the angle will change slightly. An additional complication is produced by the aerodynamics also changing as the bullet slows down causing further changes in the bullet angle. The changes in angle are going to be small and gradual and their effects on the POI will get less as the bullet gets nearer to the target. I am not sure you would call it parabolic, more like a not quite straight line. Of course in assuming a constant percentage of down wind drift then a curved variation in jump with range is assumed.