Just remember that every time you change it around you will be stirring up the bottom. This could give you algae problems. Also when you change them around trim the roots and remove leaves that are showing signs of deterioration.
I agree.It all depends on what type of plants you are growing.
If the species has very little roots and enjoys floating it doesn't matter.
If the plant has lots of roots then everytime you mess with it you damage the root system. This can greatly hamper the growth of the plant and kill some plants that are more sensitive.
Generally it is best to keep moving the plants to a minimum. One of the most difficult tricks when working with plants is arranging them for their adult size when they are just babies. Not the easiest thing to do when your are never quite sure how the plant will react in your tank. I'm pretty bad at it myself.