I noticed something funny at the range last night, and I remembered something from last winter. When I aim not only in a certain direction, but at a certain height with my driver, I'm more likely to hit it that high than when I simply aim in a direction. It doesn't happen all the time, but I would say 2/3 times the ball will travel higher if I set a mental target that is higher (at least within reason for a driver). Is that normal? Should we be aiming at a certain height in addition to direction with the driver?
I suspect that in the process of aiming (for height) that you're making small stance adjustments (probably in spine angle) that effects the angle of attack of the club face at impact.
By that I mean that those aiming adjustments you're making means the club comes at the ball flatter or maybe a little more on the upswing than usual. That small difference in the club head angle at impact will result in shots of different heights. For example, if you increase your spine angle (tilt away from the target) you'll come at the ball with a slightly ascending swing path which adds loft and gives you a higher ball flight.
What you need to establish is your "normal set-up". What set-up position is your "normal" for your normal drive with normal ball height? You should write down your feelings and what you see. Better yet you should video your "normal" (and then save it) so if you ever have problems in the future you can refer to it.
What you should aim for each time is your "normal". Then if you need a higher or lower shot you can adjust from your normal position.
I hope this answers your question. If it doesn't please feel free to ask again.