Depends highly on the food as well as other factors such as activity level, growth spurts and metabolism. If once they are fully grown they meet the standard, then you are feeding the right amount.
Example, Ringer is 74-75 lbs and has been for a couple months. I got him at 64lbs from his breeder and he was being fed Beneful at somewhere between 6 and 8 cups a day! He was still too skinny, always begging for food and wasn't growing despite the massive amount of food. Now that I am feeding him Canidae and he is 10lbs heavier, I am only feeding him 3.5 cups a day. He is a year old, plays most of the time I am home and burns a minimum of 30 minutes a day in the back yard in addition to the hour or so walks we take daily.
Pros from finding the right food:
No diarrhea
MUCH less poop to scoop
Allergies gone
No need for yogurt/pumpkin/digestive enzymes in food
Less overall cost for food
Less overall cost of ownership (fewer vet visits, no need for stool hardners allergy meds,...)
I don't think I exactly answered your question but hopefully there is enough info to help you answer it yourself.