It is correct as stated---as far as it goes. Sometimes you may have the ability to adj the front sight. If you do then obviously you push it the opposite of the desired strike. If you reach a point on a rear sight sush that you are out of adjustment and still ''too high; too low'', you'll have to get a proper height rear that gives proper travel OR adj the front to compensate.
Most all pistols and revolvers will have enough travel with factory sights. When dealing with the ''specialty pistols'' that have sights replaced you'll have to ''use all of your powers and talents'' to get them where you want them. rp