Hmmm - I can't say that it's a bad idea, but you might not end up saving as much powder as you think. Sometimes increasing the charge will not only raise the point of impact, but also throw it a bit off to one side due to the increased flex/vibration of the barrel with a heavier charge. If that happens, you'll still have to change your sights/scope, shoot again, and perhaps again to get it right on.
What I would do instead of that is (1) try to find out a ballistics chart for the load and bullet you will be shooting. This will tell you how high or low you will be at different ranges. (2) Then start at 25 yards and adjust to get your bullet to hit where it should be there. Make sure you have a rock solid rest and get your bullet precisely correct left/right. I would not necessarily shoot a 3-shot group for this, but probably 2 to make sure you have consistency. (3) Then move your target out to 75 or 100 (or whatever you expect to be shooting) to check to see if there is another adjstment necessary. Assuming there is no wind to drift your shots, you should be very close by using this method and use a minimum amount of powder.